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Technology

Serial ATA Technology Explained 468

Posted by CowboyNeal from the atat-technology-still-only-fictitious dept.
Mike Parsons writes "Explosive Labs has an interesting article on Serial ATA . Here is a quote: 'In the rapidly moving computer industry, there are rarely the kinds of revolutionary changes like what is about to take place in secondary storage segment. Soon the hard drives and configuration methods that have existed since the origins of the personal computer will change forever. The basic IDE technology has been around for nearly twenty years. When the lifetimes of other computer components like CPUs and video are measured in months, twenty years ago seems like prehistory.'"
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Serial ATA Technology Explained More

Serial ATA Technology Explained

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  • Prehistory? Depends on context (Score:5, Insightful)

    by Hentai ( 165906 ) on Wednesday October 23, 2002 @08:03PM (#4518511) Homepage Journal
    Think about this - how long has RS232 been defined? How long has the PC's parallel (i.e., LPT1) pin-out been defined? How long has the VGA pin-out been defined? How long has the PC keyboard pin-out and protocol been defined? A lot of things change pretty fast; a lot of things stay around forever. It all depends on whether upgrading them is worth the cost in the long run.

    • Re:Prehistory? Depends on context (Score:5, Interesting)

      by Thurn und Taxis ( 411165 ) on Wednesday October 23, 2002 @08:17PM (#4518602) Homepage
      For that matter, how long has the x86 architecture been defined? How many /. readers were even alive when the 8086 was released? I know I felt a few grey hairs pop out when a co-worker told me his first computer was a 286. Only superficial changes in computer architecture have happened during our lifetimes. The way we interact with computers is totally archaic, just like the way we interact with banks, cars, washing machines, and televisions is archaic. The world is dying for some clever person to come up with a way to make it just as easy to ask a machine to do something as it is to ask a person to do something.
      • RS232:
        Three modifications. Most recent in 1991
      • Parallel port:
        Does anyone still use this? In the past 6 years, any printing I've done has either been off a network printer or at Kinko's
      • VGA pin-out:
        Here comes DVI!
      • keyboard pin-out:
        USB!
      But yes, I acknowledge your point.

    • Re:Prehistory? Depends on context (Score:5, Informative)

      by dutky ( 20510 ) on Wednesday October 23, 2002 @08:28PM (#4518676) Homepage Journal
      With one exception, none of the "standards" you mention are either very old or very standard. The exception is, of course, RS-232, which was defined in 1969 by the Electronic Industries Association of Washington D.C. (my home town). All of the others are relative infants:
      • The PC parallel port was defined, in a very loose manner, by IBM when the IBM-PC was introduced in the early 1980s. The original PC parallel port was unidirectional and good for little else than driving a printer. While a number of manufacturers offered bi-directional versions of the PC parallel port (including IBM, in the late 1980s, with the IBM-PS/2) no actual standard existed until the release of IEEE-1284, in the mid-1990s, which gives us the modern ECP/EPP option.
      • The VGA pin-out dates from the introduction of the IBM-PS/2 in 1988/1989.
      • The PC keyboard pin-out and protocol have only been around since the introduction of the IBM-PC, and have undergone at least two revisions, first for the IBM-AT keyboard, and second for the IBM-PS/2.
      The reference to IDE having been around for 20 years is a pretty dubious one, unless you count IDE as just a variation on the vernerable IBM-PC expansion bus. (commonly known as the ISA bus) Still, 20 years ago, there was no such thing as IDE, even as a glimmer of a hope in anyone's eye.
      • The IDE I/O register mapping/interface dates to the ST-506 interface (early '80s), defined by Shugart Technologies.

        The (16-bit) IDE physical interface is an extension of the AT bus (1984).

    • Re:Prehistory? Depends on context (Score:5, Funny)

      by Call Me Black Cloud ( 616282 ) on Wednesday October 23, 2002 @08:29PM (#4518681)
      You're correct. Consider the length of time the original male-female coupling system has been around...
    • I don't have any of those ports on my computer; it's got USB and DVI instead.

  • SCSI? (Score:4, Insightful)

    by GreyWolf3000 ( 468618 ) on Wednesday October 23, 2002 @08:04PM (#4518516) Journal
    Soon the hard drives and configuration methods that have existed since the origins of the personal computer will change forever.

    All of IDE's shortcomings are fixed by SCSI (except for a small degree of added complexity). SCSI hardware is more expensive, and rarely does it come built-in to motherboards.

    If more people used it, it would be a cheaper solution, and would fix all of IDE's problems without re-inventing the wheel--it's a solution that, right now, works.

    15k rpm scsi drives get seek times in the low three range--that's three times faster than your average 5400 rpm ide hdd.

    • Re:SCSI? (Score:5, Funny)

      by stratjakt ( 596332 ) on Wednesday October 23, 2002 @08:11PM (#4518569) Journal
      > All of IDE's shortcomings are fixed by SCSI

      You mean the oversized 40-conductor ribbon cables are solved by 68 conductor ones?

      > If more people used it, it would be a cheaper solution

      Heh, sure it would.

      > 15k rpm scsi drives get seek times in the low three range--that's three times faster than your average 5400 rpm ide hdd.

      And 10x more expensive.

      You are the first SCSI fanboy I've ever seen.

      Now bring on the cheap!

      • Re:SCSI? (Score:2, Informative)

        by shepd ( 155729 )
        >You mean the oversized 40-conductor ribbon cables are solved by 68 conductor ones?

        Nope, they're solved by using high-density cable connectors, which IDE still hasn't figured out with 80-pin cables (instead IDE just cheats).

        >And 10x more expensive.

        Because... why?

        Nobody is buying, that's why. Lower speed SCSI drives are still available, but are still expensive because IDE is stuck in everyone's heads as the only storage method for a PC.

        >You are the first SCSI fanboy I've ever seen.

        You haven't been here very long. Let me be the first to say welcome! :-)

        • Re:SCSI? (Score:5, Insightful)

          by G-funk ( 22712 ) <josh@gfunk007.com> on Wednesday October 23, 2002 @09:28PM (#4518843) Homepage Journal
          it's got nothing to do with how common it is, scsi is expensive because it raises the percieved value of the product, and it's common knowledge that this "elite"ness of more expensive alternatives to a product aid sales.

          In short, it's expensive because they like it that way. There's no shortage of scsi drives, they're not particularly more expensive to produce.

          • Re:SCSI? (Score:5, Insightful)

            by GooberToo ( 74388 ) on Wednesday October 23, 2002 @09:56PM (#4518975)
            Someone mod this guy up. He, "gets it!" SCSI is expensive because it's the premium, top-shelf product. Period. SCSI is expensive for the same reason that diamonds are. Both are highly desired but have no more value than the next drive (be it IDE or rock).

            In other words, they are expensive because people want to keep them that way!

            • Re:SCSI? (Score:4, Insightful)

              by gad_zuki! ( 70830 ) on Thursday October 24, 2002 @12:46AM (#4519702)
              > SCSI is expensive for the same reason that diamonds are.

              Not at all. Diamonds are a controlled cartel and price-fixing is par for the course. SCSI in mass production anywhere near how much IDE stuff gets made will drop the price to the point where it would be affordable to sell it to the home market. Or so the theory goes.

              If diamonds weren't price-controled they would be incredibly cheap. Read about it here: http://www.professionaljeweler.com/archives/news/2 000/020300story.html

      • Re:SCSI? (Score:4, Interesting)

        by Enry ( 630 ) <enry@@@wayga...net> on Wednesday October 23, 2002 @08:20PM (#4518624) Journal
        > You mean the oversized 40-conductor ribbon cables are solved by 68 conductor ones?

        No, I'd guess the 80 pin ones that include power and configure the drive's ID, and allow you to just slap the drive in and let it go. IDE has NOTHING with that configurability.

        > You are the first SCSI fanboy I've ever seen.

        Now you've seen two.

        Don't get me wrong - for home use, SCSI is overpowered. But if you're talking anything bigger than a desktop, make mine SCSI.

        • Re:SCSI? (Score:2, Insightful)

          by stratjakt ( 596332 )
          Well, yeah, SCSI will always have a place in high end workstations and servers.

          But my new desktop (as I've already posted) has an onboard SATA RAID controller.

          Personally I cant wait to get some workstation-level performance at desktop-level prices.

          And no more big ugly cables uglying up my side window. These little cables that came in the mobo box are going to look pretty good in there.

          It's an improvement over PATA no matter how you slice it. It promises to be cheaper, faster, easier, hot-swappable, self-powered.

          I dunno why people are complaining. Well, yes I do. This is slashdot, and any new technology is equated with a bid for world dominance from [CORPORATION].

          • SCSI could scale down to fit desktop needs, but it wouldn't since IDE has such a high market share, it would start out more expensive. SCSI is expandable and scaleable (in both directions).

    • Re:SCSI? (Score:2, Interesting)

      by Stigmata669 ( 517894 )
      "All of IDE's shortcomings are fixed by SCSI (except for a small degree of added complexity)."

      Yeah, even if your statement were true. Price is a huge shortcoming in technology today, especialy when most people can't use the preformance hardware that they own.

      I strongly support the development of IDE standards. There are many situations when you need lots of hard drive space without bleeding edge preformance. Try to find a solution for doing a small (350GB) backup server to add to a tape backup system, you find 200GB IDE drives for the price of a 18GB SCSI drive. A thousand people will try and explain why the SCSI is a better deal because its more reliable and faster, but backing up 350 gb on IDE costs about $650, and on SCSI costs aboyt $4000. I don't believe the demand is the reason for the premium price for SCSI, but the hardware... It's just more expencive to make.
      • Yeah, even if your statement were true. Price is a huge shortcoming in technology today, especialy when most people can't use the preformance hardware that they own.

        Here's why your point is moot: First, IDE drives are only cheaper because it's more widely used. Secondly, SCSI can scale to low end needs--you're not locked into having to be fast. What has happened is that SCSI has found its nitch in the server market. SCSI could downscale very well

        I don't believe the demand is the reason for the premium price for SCSI, but the hardware... It's just more expencive to make.

        That's only true because SCSI hard drive makers have to make fast server-oriented drives. If they had a desktop nitch, they could sell slower drives for similar prices--as it stands they couldn't compete.

        SCSI can serve both low-end and high-end needs, if folks would give it a chance. The article's mentioning of SCSI being too loud is ridiculous--internally they all work the same. 15k rpm hard drives by nature make a lot of noise.

    • Re:SCSI? (Score:4, Insightful)

      by puppetman ( 131489 ) on Wednesday October 23, 2002 @08:17PM (#4518609) Homepage
      Lots of motherboards come with SCSI. Most Intel server boards do, as do boards from SuperMicro (P3TDE6-G, S370DL3, P3TDDR), Tyan (S2721, S2720), etc, etc. I've been looking into them for server upgrades (I just don't have time to track down a few dozen model numbers).

      SCSI does have a faster spin time, and is in general much faster, but for small, random chunks of data, it can be slower (but it's a small penalty in a rare case). The width of the SCSI bus is much better (320 MB/s for SCSI 320), assuming you have alot of drives in big striped arrays.

      Don't forget - most IDE drives (except for a few premium models) just had their warranty chopped from 3-years to 1-year. Not a reflection on declining quality of IDE drives, but rather the economics of the market place. SCSI still has decent warranties, and they last longer regardless.

      SCSI is (much) better; could they be as cheap as IDE if everyone used them? Probably pretty close. But it's a chicken and an egg thing. Home-users don't buy them because they are expensive, and they are expensive because consumers won't buy them.

      Ironically, SCSI stands for Small Computer Standard Interface, but SCSI is most frequently found in Servers (large, not small computers), in large RAID arrays. And more ironically, the SCSI drives usually used in RAID (Redundant Array of Inexpensive Disks) usually are not that inexpensive at 3x the cost of IDE.

      • Re:SCSI? (Score:3, Informative)

        by dan the person ( 93490 )
        "Ironically, SCSI stands for Small Computer Standard Interface, but SCSI is most frequently found in Servers (large, not small computers), in large RAID arrays. And more ironically, the SCSI drives usually used in RAID (Redundant Array of Inexpensive Disks) usually are not that inexpensive at 3x the cost of IDE. "

        You have to look at when these terms where invented.

        The following definitions applied back then:
        Small Computer = a computer that did not require an entire building to house it.
        Inexpensive = cheaper than solid state.

    • Re:SCSI? (Score:3, Informative)

      by km790816 ( 78280 )
      Read the article.

      The problem with SCSI is heat and noise, things that work fine in a server room, but are bad for the home user.

      I had SCSI for a while in college. It was cool to show off, but having to turn up my TV to hear over the jet engine in my PC was annoying.

      • Re:SCSI? (Score:4, Insightful)

        by Sneftel ( 15416 ) on Wednesday October 23, 2002 @08:33PM (#4518706)
        Err... since when did a communications bus generatte any appreciable noise or sound? Nothing distinguishes the dynamics of hard drive operation between IDE and SCSI. SCSI hard drives tend to be faster, since people who buy them tend to want to attach them to servers, but if pushed into the home consumer arena you'd see SCSI drives with exactly the same noise/heat output as IDE drives. This is an example of market-driven, not technology-driven.

      • Huh? (Score:4, Insightful)

        by WD ( 96061 ) on Wednesday October 23, 2002 @08:37PM (#4518741)
        What on earth does the type of interface have to do with heat or noise?

    • Re:SCSI? (Score:3, Informative)

      by egarland ( 120202 )
      > All of IDE's shortcomings are fixed by SCSI.

      Heh. Here's a list of IDE's shortcomings SCSI makes worse:
      • cable size
      • interoperability issues caused by multiple drives per cable
      • bandwidth per drive
      • cost of the controllers
      • cost of the cables
      • cost of the drives
      • Low reliability caused by multiple devices physically attached to the same cable that can bring parts of the bus or the whole bus down

      The bandwidth per drive thing is one of the great things that SATA brings to the table. With a modern large SCSI setup it seems like you have a lot of bandwidth but on a per drive basis you really don't. 160MB/s divided by 12 drives = 13MB/s (1980's speed). To contrast that look at a 12 drive 3Ware SATA controller. That has a full 150 MBytes/Sec to each of the 12 drives.

      To see the usefulness of this take the example of a 12 drive RAID 5 array doing a rebuild while the server is trying to read from the drives. The controller has at it's disposal 1800 MB/s worth of bandwidth that it can use. It can run those drives as fast as they can go keeping the write buffer full on the drive it's rebuilding and using the leftover bandwidth to service the server's requests. Modern ATA drives [storagereview.com] can read at up to 56 MB/s. With 12 drives you get a total of 672 MB/s throughput which is far more than even the new Ultra320 SCSI is capable of. With newer faster drives and 16 drive RAID controllers this problem gets even worse.

      > If more people used it, it would be a cheaper solution

      SCSI is quite widely used. There is a lot more SCSI out there than SATA and yet a motherboard with a SATA raid controller costs about the same as one without it whereas a motherboard with a SCSI raid controller on it costs about 3 times as much. SCSI is simply an expensive, complicated technology to implement.

      >15k rpm scsi drives get seek times in the low three range--that's three times faster than your average 5400 rpm ide hdd.

      The low seek times are a result of expensive server class drive technology, not of the interface. Seagate could just as easily drop a SATA interface on those 15K Cheetah drives and I suspect in the near future they will because:

      All of SCSI's shortcomings are fixed by Serial ATA

      Yea, I know, it's a cheap shot but really SATA is poised to replace SCSI in most of the markets SCSI still occupies. SCSI was mostly popular in server systems because of it's hot swapablility and plug and play operation (no jumpers to set on 80 pin sca drives.) These are advantages that Serial ATA shares. Motherboard integrated SATA RAID will take over for SCSI RAID in server class systems because of cost, size, power and bandwidth issues. 8 - 16 drive SATA RAID arrays will take over the low to mid-size storage array market. (If you can count 4.8 Terabytes as mid size.) Fiber channel will be left for SANs and large storage arrays. SCSI will be relegated to connecting external drive systems but I imagine fiber channel will eventually take most of that market.

      People who like SCSI will probably like SATA even more. It will be faster, much cheaper, more reliable, more compatible, and easier to maintain and troubleshoot. True, you won't be able to run a printer or scanner off it but I doubt there will be a lot of people missing that particular piece of SCSI functionality.

      • Re:SCSI? (Score:4, Informative)

        by adolf ( 21054 ) <flodadolf@gmail.com> on Thursday October 24, 2002 @03:04AM (#4520096) Journal
        There is a certain elegance to such things as SCA backplanes which ATA (in any incarnation) will never achieve.

        Which is another point:

        They botched SATA by not including power on the bus, having no standardized connector locations, and (at least so far) having no facility for connection of external devices.

        The 1-device-per-wire rule of SATA is another detriment: Sure, the cables are fairly small, but can you imagine the rats nest that would be a 12-device SATA system?

        SCSI daisychaining is an easy fix for that, and now-common LVD SCSI is quite able to support this number of devices with a single ribbon. And LVD, by its differential nature, is quite resistant to the electrical problems introduced by slice-and-jacket cable rounding techniques that are all the rage these days..

        Oh. And you've got your math wrong, Son:

        It doesn't matter if 3ware makes a controller with 12 150MBps ports. The 12-port Escalade 8500 you speak of has a 64-bit 33MHz PCI interface, topping out at no more than a paltry 264MBps to be shared by all connected devices.

        If you're serious about throughput, try something like this [adaptec.com]: Two 320MBps channels on a 64-bit, 133MHz PCI bus. Good for real-world transfer rates in the realm of 640MBps, more than twice that of the 3ware product, while keeping a good portion of the PCI bus free the -other- 30 SCSI devices you've got plugged into it.

        And none of this says anything about the benefit of SCSI for the home user:

        Just bought a new DVD-R, but don't want to toss your old but dead-solid Plextor? SATA requires you to buy another port. SCSI just requires you to plug it in.

  • Now you know why there isn't a Universal Parallel Port.

    Shame it took the original IDE developers 20 years to cotton on. I'm sure this has been on the verge of becoming mainstream tech for about three years now. Some people must really love their ribbon cables.

    The Tab! You forgot the Tab!
  • Faster transfer rate from the HD to ATA adapter is a good idea; however, wouldn't it be useless if you connect a 5400RPM HD with no cache to it?

  • Only if... (Score:2, Insightful)

    by SirKron ( 112214 )
    Serial ATA will only take off if it is not more expensive than parallel ATA. If we (meant users) want to spend more we would buy SCSI. What I want is a low cost way to stipe 4+ drives at home.
    • This gives it to you. The main problem with IDE-RAID is fucking around with cables and a standard that doesn't support hot-swap.

    • even cheaper (Score:3, Interesting)

      by lseltzer ( 311306 )
      The whole point of it is to be at least as cheap as parallel ATA, even cheaper. The connectors will be smaller and cheaper for example. It should also make system design more flexible since you won't have parallel ATA's infuriating cable length limits.

  • yeah, yeah, yeah enough with the sales pitch (Score:3, Funny)

    by stratjakt ( 596332 ) on Wednesday October 23, 2002 @08:07PM (#4518549) Journal
    Where are my drives?

    I got a shiny new SATA RAID controller on my new motherboard, now when the hell am I gonna get a couple of 80 gig cheap, fast SATA drives to put into a striped set?

    huh? huh?

  • FIREWIRE? (Score:4, Interesting)

    by cybercomm ( 557435 ) on Wednesday October 23, 2002 @08:08PM (#4518553) Homepage Journal
    So...why don't we use firewire? Isn't it faster than SATA? And the upcomming Firewire IEE 1394b should double the firewire speed to ~800mb/s. And let's not forget the fact that there are firewire HDD-s and other perhipeals on the market (though they are generaly external) or maybe, could this have anything to do with INTEL's desire to controll all components? I don't see the price as a limiting factor either.

  • This just looks expensive. (Score:5, Interesting)

    by jericho4.0 ( 565125 ) on Wednesday October 23, 2002 @08:08PM (#4518557)
    The first generation doesn't look that impressive, as shown by the selling points given by the author. Thinner cables, up to a meter long?? Ok, sounds nice, but not worth paying extra for, for my needs. Serial ATA wil debut at 150 mb/s, not really an improvment at all.

    The author then goes on to note that the 'roadmap' calls for the 2006 version to run at 600mb/s, which fits nicely with my roadmap to world domination in 2005. ...Ummmm, yeah, we'll see.

    Although looking at the list of upcoming products and the manufactures making them, I don't doubt we'll all be useing this in a few years.

    • Re:This just looks expensive. (Score:4, Informative)

      by pope nihil ( 85414 ) on Wednesday October 23, 2002 @08:14PM (#4518589) Journal
      Actually they said SATA 3 (600 MB/sec) will debut in 2007.

      I was a bit confused by this article. They talk as if this thing is the Second Coming of Christ, but then they talk about how desktop pcs are just going to keep taking baby steps. Also at the beginning of the article they say that serial seems to be a step back from parallel (ya think?) but it is faster and better and Oh! Look! An elephant!

      • Re:This just looks expensive. (Score:5, Informative)

        by photon317 ( 208409 ) on Wednesday October 23, 2002 @08:27PM (#4518667)

        The battle between serial and parallel communications is neverending. Show me a Serial WAN connection like a DS3, and I can say "Well, since you never send partial bytes, we could strap 8 of these side by side, send one byte at a time with the bits split up over the 8 DS3s in parallel frames, and we get an 8x speed improvement that's usable by a single connection and no additional latency".

        Or show me a parallel bus like IDE, and I can say "Look, having all those data lines next to each other causes additional interference we have to account for, and they're bulky, cost more, overly complex, blah blah. If we just put a serial bitstream on a pair of wires, it would be so much simpler that for the same cost we can turn up the bitrate more than enough to make up for the lost parallelism."

        It's all the same. Various communication technologies tend to rise and fall, serial replacing parallel replacing serial replacing parallel ad infinitum. In some cases (like PCI busses) parallel just makes a lot more sense, but in a lot of cases (network stuff, storage stuff especially) there's a tradeoff where both are better and worse than the other in different ways. You could just pick one and stick with it and do you incremental improvements, but the occasional switcheroo provides upgrade revenues and more user "wow" factor and buzzwords.
        • Eh, parallel is on the way out for good. You've obviously never heard of a little thing called clock skew. It's what makes your DS3 example impractical since the bits won't all arive at the same time, with the run lengths you're talking about with a DS3 the potential difference would be too large to effectivly compensate for.
    • It is an impressive jump ahead, and it's not going to be much more expensive. It's estimated that Serial ATA interfaces will be less than $10 more expensive than their parallel counterparts, and that will go down once it becomes more popular. Also, it's not 150 M-bits/sec, it's 150 M-Bytes/sec. Another big advantage is that Serial ATA is that the drives will be hot-swapable. The new power connectors have extended ground plugs so that the grounds contact before power... also drives will get to use a new voltage line (+3.3V) that they didn't get before.

      Another interesting thing about the technology is that drives that are currently using the parallel SCSI interface will be moving to either SAS (Serial-Attached-SCSI) or Fibre Channel. SAS will use the SCSI protocol over the Serial ATA cables, so you can get rid of those nice giant ribbons.
    • ATA wil debut at 150 mb/s, not really an improvment at all.

      Does it matter? At all? No.

      Frankly it could be 150 GB/s and it wouldn't matter in the least.

      Go look at the manufacturer specs. Read the line that says "drive to host, sustained throughput". Note that no manufacturer claims more than 52 MB/s. Reality is closer to 48 MB/s for the fastest IDE drive. That's right! We're not even exceeding ATA/66 bandwidth yet. And still people are talking about 600 MB/s in a few years. Who cares? You can't reach that throughput anyway. Not to mention that the PCI bus is limited to 133 MB/s.

      Ok, the bus speed does make a bit of difference. If the data you need is in cache then you can use the maximum theoretical bandwidth while reading from cache. So dumping a 8 MB cache via ATA-133 saves you about half a millisecond over ATA-66. You noticed that, right?

      The advantages of SATA have nothing to do with the bus speed. The longer cable is useful in a select few tower cases. The hot swap will be nice for a small percentage of enthusiasts and idiot admins (I'm not a SCSI fan boy, but if you're running a server you really should be running SCSI). The small, thin cable is useful for everyone though -- the air traps created by ribbon cables are causing more and more problems as everything runs hotter. Most drives fail due to poor cooling. Want to bet that SATA drives have a significantly lower failure rate?

  • Personally, I can't wait until it comes out... (Score:5, Insightful)

    by HoneyBunchesOfGoats ( 619017 ) on Wednesday October 23, 2002 @08:11PM (#4518573)
    ...'cause that means prices will drop on hard disks that I can use.

  • too bad that (Score:3, Interesting)

    by LuckyJ ( 56389 ) on Wednesday October 23, 2002 @08:17PM (#4518607) Homepage
    All data goes through the PCI bus...and it's bandwidth is only 133MB/sec theoretical. So, what does 400/800/anything else greater than about 100MB/sec in a media interface get you? Not much!

    Ever read the actual throughput specs on a drive? The media throughput is not much more than 40MB/sec!!! Read the data sheets, people!

    Add this all up and what do you get? Ripped off is about it!
    • Haven't seen 64bit PCI busses running at 66 or 133 Mhz, have you?
    • 1. The "PCI problem" is going to get fixed next year when the next gen busses (Hypertansport, PCI-X, etc.) start appearing on motherboards.

      2. That 40MB/s is sustained throughput, HDs can burst from cache much faster than that. This is going to become more of an issue as HD manufactures have finally started putting more cache on their drives.

    • Re:too bad that (Score:5, Informative)

      by cheezedawg ( 413482 ) on Wednesday October 23, 2002 @08:31PM (#4518690) Journal
      All data goes through the PCI bus

      No it doesnt. Data goes through the PCI bus if the address is not claimed by something else along the way. That means that everything from the southbridge up is not limited by the PCI bus bandwidth. That means that integrated SATA controllers (not available until next year) are only limited by the bandwidth between the northbridge and southbridge.

      Ever read the actual throughput specs on a drive?

      Drive throughput has been steadily increasing, and it is predicted to pass up PATA within a few years, and that is not counting RAID striping or the 8 MB drive caches. Its always desirable for the bottleneck to be the drive rather than the controller.

    • Re:too bad that (Score:5, Insightful)

      by ltwally ( 313043 ) on Wednesday October 23, 2002 @08:46PM (#4518808) Homepage Journal
      For starters, the PCI spec isn't limited to 133 MB/s. PCI 2.1 specs allow for 66 MHz 64-bit transfers, which equals 528 MB/s. PCI 2.2 specs allow for PCI-X mode, which adds 133 MHz 64-bit transfers: 1056 MB/s.

      That being said, it is entirely possible to reach throughputs in excess of 133 MB/s using a PCI bus... though currently most desktop motherboards do not support anything faster than 133 MB/s. In time this will change as NICs, hard disks, and other gear requires it.

      And your hard disk performance is barely par by today's standards. IDE drives are currently topping 50MB/s, while SCSI gear is hittin > 70MB/s. Though I am a SCSI man, i can see the future need for SATA. Right now it may be mainly a marketing ploy... But in a couple years it will be a necessity. Parallel cabling is nearing the end of the road.. all those wires in a cable allow for too much signal interference. Serial is the answer. Though it has less wires, the dramatic increase in signal strength allows for insane transfer rates.

      Anyhoo.. personally I don't see any reason to go out and buy a new system just to have SATA. At the current it offers few advantages.. but in the not so distant future it will be a necessity for desktop systems. As for me, i plan on going Fibre-Channel SCSI :)

  • More Information (Score:5, Informative)

    by leibnizme ( 264472 ) on Wednesday October 23, 2002 @08:18PM (#4518613)
    Since the site is slashdotted, here are further links about Serial ATA:

    Cnet [com.com]

    SATA and ISCSI [infoworld.com]

    Intel Dev Paper [intel.com]

    Maxtor White Paper [maxtor.com]

    • Re:More Information (Score:3, Insightful)

      by Salamander ( 33735 )

      I really love how the Maxtor paper compares SATA to parallel ATA, USB (?!) and Firewire...but not to SCSI or FC. I wonder why that is. Actually, no I don't. ;-)

  • Not important yet (Score:3, Insightful)

    by thetzar ( 30126 ) on Wednesday October 23, 2002 @08:19PM (#4518618) Homepage
    I can't wait to get my hands on some SATA devices. However, we're still stuck with PCI, here on the desktop end. WHEN will we finally start seeing the old original PCI spec phased out on the desktop end? Not until then will new technologies like SATA be able to shine. Bus bandwidth is everything these days.

  • RDRAM Redux (Score:5, Interesting)

    by grendelkhan ( 168481 ) <scottricketts.gmail@com> on Wednesday October 23, 2002 @08:21PM (#4518630) Journal

    This sounds remarkably like the plugs we got for Rambus RDRAM: serial interface is better than parallel, first gen won't see real performance gains, stick with us kids, this is gonna be really good.

    I see a decided lack of Sun, IBM, AMD, or HP listed in the adopters, which leads me to believe that this is much like the above. Sorry guys, I'm not riding the first wave of any new tech on my salary. I'll sit on the sidelines for awhile and see how this pans out.

    • Excpect SerialATA is actualy cheaper to implement than ParallelATA and there's no latency issues like those that killed RDRAM, SATA is unquestionably faster than ATA100. SATA will be taking over in place of parallel, it's only a matter of time.

    • SATA == Future (Score:3, Informative)

      by nuxx ( 10153 )
      Note that Sun, IBM, AMD, nor HP are disk manufacturers. (Well, IBM might still be, my memory is being bad tonight, but I digress...) Some AMD and Intel motherboards are already coming with SATA RAID interfaces. Intel is right behind the technology, as they are a chipset manufacturer. AMD isn't. VIA, a chipset manufacturer is, along with a ton of other [serialata.org] manufacturers who are core to desktop/workstation storage. Just because the big power houses that you name aren't on board doesn't mean anything. Most of these places leave their disk interfaces up to someone else. And those companies *are* adopters.

  • SCSI TROLLS: READ THIS (Score:4, Interesting)

    by Vengie ( 533896 ) on Wednesday October 23, 2002 @08:29PM (#4518682)
    For all of you waxing locquatious on the merits of scsi....please read the article, noticeably:
    SCSI drives are notorious for their noise, heat and vibration levels. These low points are not acceptable at the consumer level. Noise and heat don't matter too much in huge server rooms, but they can quickly become a problem in desktops. Unfortunately, this means that the extremely low seek times and high spindle speeds that make SCSI drives so fast are not available in consumer market. Basically until cooler, quieter, smoother drives can be manufactured in high volume, desktop hard drives will continue to make baby steps in speed.

    For the time being, IDE isn't going anywhere.
    NOISE & HEAT will tend to outweigh (relatively) minor performance gains in consumer systems. (Enterprise hardware is another matter entirely)
    sigh....we need to start using those annoying javascripts that make people read the article BEFORE posting.
    • Not to mention the #1 stumbling block for most people: price. SCSI costs significantly more for comparatively little actual performance benefit. On a server, which is hard-drive intensive, this performance difference is big enough to make SCSI worthwhile. On the desktop, on the other hand, it costs more, allows smaller sizes, and apparently makes more noise and heat. No wonder IDE is here to stay...

    • IDE TROLLS: READ THIS (Score:5, Insightful)

      by darkwiz ( 114416 ) on Wednesday October 23, 2002 @08:48PM (#4518816)
      SCSI drives are notorious for their noise, heat and vibration levels. These low points are not acceptable at the consumer level. Noise and heat don't matter too much in huge server rooms, but they can quickly become a problem in desktops.

      For the time being, IDE isn't going anywhere.
      NOISE & HEAT will tend to outweigh (relatively) minor performance gains in consumer systems. (Enterprise hardware is another matter entirely)
      sigh....we need to start using those annoying javascripts that make people read the article BEFORE posting.


      Absolutely. But this has nothing to do with SCSI, it has to do with the high spindle speeds at the bleeding edge. The card on the underside of the drive is not making that ear shattering racket. They even acknowledge that in your quote.

      SCSI is better than ATA. Even SATA. ATA has been trying to catch up by stealing some of the best parts of SCSI (like TCQ). But it just isn't quite as good yet. Quite frankly, I agree with the majority of SCSI zealots: if the damn PC makers would embrace SCSI, then the cost of SCSI would come down to near parity from the volume of sales.

      Now, is SCSI better for your average Joe? Maybe not significantly. Neither is 7200 vs 5400, 2MB vs 8MB buffers, or 8.9 vs 9.1 ms access times.

      However, if they could use one cable to connect 15 devices in their tower, they'd be alot happier than having the 8 cables they'd need to do it with current IDE tech (let alone IDE's relative inability to be used externally).

    • Re:SCSI TROLLS: READ THIS (Score:5, Insightful)

      by mosch ( 204 ) on Wednesday October 23, 2002 @10:02PM (#4519007) Homepage
      That has nothing to do with SCSI. The only reason it's even remotely related is because people have a tendancy to buy SCSI drives like this one [maxtor.com], which is a 15K RPM drive with a 3.2ms seek, and the ability to sustain a 75MB/sec data throughput rate, whereas high-end ATA drives like this one [maxtor.com] spin at 7200 RPM, have a 9ms seek, and don't list their maximum sustained data throughput rate on the data sheet.

      Is IDE appropriate for the desktop? absolutely.

      Will retards continue using IDE in applications where SCSI is far more appropriate? definitely.

      Does your post make any fucking sense at all? nope.

  • I think I read in somewhere that SATA could do command queueing. Does that mean that it will allow the driver to re-order them like SCSI drives? That was, I think, one of the main advantage of SCSI over IDE/ATA drives.. That they could re-order the commands and send answers in a different order to maximize performance.

    • Re:command queueing (Score:4, Informative)

      by cheezedawg ( 413482 ) on Wednesday October 23, 2002 @08:38PM (#4518753) Journal
      Yes- but AFAIK command queuing is not implemented in a lot of the 1st generation controllers because it can break backwards compatibility with PATA software. Most vendors went for an easy upgrade path instead. Look for command queuing in the next generation of controllers.

  • whats new? (Score:2, Funny)

    by nonane ( 305432 )
    narrower flexible cables is all the SATA has to offer? its like switching from a two-headed screw driver standard to a philips one. the heads are different but the screw gose in the same way. give me a few features of SCSI in an affordable package and then your talking.

    on the other hand: installing more ram/new-cpu wouldn't be such a pain .. 2 hard disks, a dvd and cd writer later your computer would have enough ribbons to host a toddlers birthday party. and to get rid of the freaking master/slave shite ... ahhh. damn it I want SATA!

  • I want the connector! (Score:4, Informative)

    by aronc ( 258501 ) on Wednesday October 23, 2002 @08:33PM (#4518711)
    Personally, I could give a rats butt about the speed. I don't want SATA so my drives go faster. I want it so I'm not having to spend twenty minutes doing finger gymnastics everytime I need to do _anything_ in my case.

    Is it worth upgrading for? No, probably not. But id damn sure is worth waiting an extra few months for that next machine to save the hassel of those f'ing ribbon cables.

  • ridiculous (Score:5, Funny)

    by tps12 ( 105590 ) on Wednesday October 23, 2002 @08:35PM (#4518721) Homepage Journal
    Why are they wasting their time on this ancient technology? Serial is too slow to sync my damn Palm Pilot. I can't even imagine what it would be like to try and transfer 60GB of media files over it. These companies should just accept that USB is the way of the future (no extra power required either!) and get to work on something that stands a chance of selling.
  • I've been waiting for Serial-ATA ever since reading about it. Faster speeds/bandwidth - which is actually finally needed in the IDE type world.

    NO MORE RIBBON CABLE. My favorite Linux configuration is 1 whatever IDE drive for the OS, 1 IDE CDROM, and two (RAID-1) large IDE's for data and configurations. Quick and cheap for non-critical type functions/services. I rolled through a complete failure on the core OS drive, CD died -- while trying to roll up in size on the RAID-1 and hit *FOUR* defective WD drives...while never losing data _and_ configurations. IBM sits in there right now... :)

    High end servers and workstations? Yeah, Serial-ATA is nice with the coming 40M/sec IDE type drives...but I'm also going to go after that 320M/sec SCSI technology too. Same IDE game, just a different connector basically.

    NO MORE RIBBON CABLE.

    Try stuffing four drives in a case. Not only is the IDE chain full, but cabling is a complete joke. Not anymore. Kind of like Firewire in the box, if you will. Except I think their screwing it up and keeping power separate where Firewire _can_ cary power to the devices.

    So instead of tiny IDE connectors in the current Firewire and external type drives there will be tiny Serial-ATA hookups. So what. Now get inside a PC (and/or Mac) and do a little work.

    With this and pricing for LARGE amounts of data ... I could see easily wanting a tall tower (remember those?) and building a rock and roll back end storage system for personal use. Quick and cheap ... and now VERY EASY to do. Personal RAID-50 500G personal array anybody?

    I could record so many hours of anything I wanted and never worry about losing it ... even with el'crap-ola IDE no-warranty technology.

    Of course when I have a few extra thousand lying around (not likely any time soon with the current economy outlook) I'd love to try SCSI-320.

    Now, IDE is rolling into ~40M/sec. Firewire *has* been ready for those speeds for a while. At least USB2 can keep up for a bit as well. Even faster drives is a must though. Firewire-2 is just around the corner (either 800 or 1.6Gbit's).

    It's sad that your typical/standard Mac type network (1Gbit) is faster than the typical drive being hosted. Your typical Windows network at 100Mbit is pretty muched caqpped by the current typical drives top performance at 10M/sec.

    Serial-ATA, oh yeah. One card (1Gbit) in the Linux box and I could saturate their bandwidth. Why not?

    Microwho?

  • SATA Linux Support (Score:2, Informative)

    by yamcha666 ( 519244 )
    I noticed this little remark:
    ... although it wont officially be supported until Microsoft's Longhorn OS, Serial ATA devices will work with all versions of Windows.

    And this made me wonder... how long will it take until Linux (and the *BSDs) support this new standard? Will it happen after Longhorn's release? Or has it already been done?

  • Bandwidth (Score:4, Insightful)

    by vlad_petric ( 94134 ) on Wednesday October 23, 2002 @08:43PM (#4518784) Homepage
    Serial is the wave of the future, and it will give ATA hard drives the bandwidth and features to compete with SCSI.

    I don't get it ... I quite agree that, as a serial bus, it'll be clocked a lot faster than IDE ... but a simple back-of-the-envelope calculation tells us that it has to be at least 8 times as fast as the current devices (it'd have to be 533 MHz to be on par with ATA-66)

    It looks like a technology whose main purpose is to make things incompatible, and thus require people upgrade more stuff. And anyway, it's not the speed of the bus the limiting factor (for the vast majority of users), but the mechanics of the harddrive (SCSI hardrives are faster than IDEs because they almost always are top-of-the-line products with higher rotational speeds - anybody saw a 15000 RPM IDE ?)

    The Raven

  • Am I missing something here??? (Score:5, Insightful)

    by Lobsang ( 255003 ) on Wednesday October 23, 2002 @10:06PM (#4519030) Homepage
    I think I am. Really.

    The article seems immensely biased and lacking in technical detail. It also raises some "dubious" points IMHO. Let's see:

    - P-ATA cables cannot be longer than 40cm. S-ATA cables can be up to 1m long:

    Granted, those cables are annoying. But really, how many times have you felt the need for a cable much longer than 40cm? People with full-sized cases may benefit, but then the author says that the current trend is "small footprint machines". So, why do I need a cable that is bigger than my server?

    Also, if you dislike flat cables, buy "rounded" P-ATA cables (available today, just google for it).

    - P-ATA connectors are big!

    Yes, they are! But you'll require at least twice as many S-ATA connectors, as only one device is supported... In the end, the real state on the mobo is going to be similar.

    - One device per controller is an "Advantage".

    C'mon... This guy must be joking. I couldn't believe my eyes when I read it! One device per controller is an *advantage*???? Why??? I wish I could add more devices (like SCSI and Firewire) to my curreny P-ATA technology. And then he says ONE is good for me? Don't think so...

    - High transfer rates are useful for multi-disk RAIDS.

    What kind of RAID? RAID 5 is slow in writes due to the computational power needed to calculate the XOR. Adding bandwidth won't help. And I can't see why or how only RAIDs will benefit from higher throughput.

    - Speed:

    Granted. It may be faster than P-ATA. But what about established technologies like SCSI and Firewire? I *think* (not sure) Firewire can go much faster than S-ATA in its initial version.

    I'm disappointed...

  • A never-ending game of leapfrog (Score:3, Insightful)

    by Salamander ( 33735 ) <jeff.pl@atyp@us> on Wednesday October 23, 2002 @10:10PM (#4519053) Homepage Journal

    Of course, no discussion of Serial ATA would be complete without mentioning the answer from the SCSI camp - Serial Attached SCSI [serialattachedscsi.com]. SAS will use the same connector as SATA, but will support longer cable lengths, multiple initiators (if you don't know what an initiator is you don't even belong in this discussion), full SCSI semantics instead of lame-o ATA semantics, etc. Even so, the SAS folks are still ceding the high end to Fibre Channel and talking about three coexisting technologies for the low-end/midrange/enterprise market segments. Sorry, kiddies, but SATA is still low-end.

    If there's one mistake you should try not to make more than once in this business, it's that competitors have been standing still since their previous generation. Announcing something brand new and having it be less than half a generation ahead of the competitor's last version is a failure.

  • SATA propagates all the crap of PATA (Score:5, Insightful)

    by mnemotronic ( 586021 ) <mnemotronic@@@gmail...com> on Wednesday October 23, 2002 @10:18PM (#4519095) Homepage Journal
    Serial ATA has kept all the truely horrible, obscure, and performance limiting features of parallel ATA (which was originally designed for 40 Mbyte drives), and shoves it down a thin cable. A course in ATA protocols will leave anyone who is computer literate going : You have got to be kidding!! What were they smoking????? The Serial spec has to maintain all kinds of bizarre, obsolete behavior just so that a SATA drive is backwards compatible with old software (i.e. that WfWG 3.11 system you've got tucked away in the closet). Throughout the history of ATA, when drive capacities climb towards the addressable limit of the spec, the protocol is kludged by a team of drunken baboons to extend it for another generation. The SATA committee munched an opportunity to drill a much-needed stake through the heart of ATA and give us a new interface for the next 20 years. Instead we get a change in connectors for a protocol with it's feet firmly encased in the concrete of MS-DOS 2.

    Firewire (1394) was killed by Apple's licensing fees and Intel's sudden backstabbing policy change on building it into south-bridge, along with their NIH attitude. There existed working 1394 Device Bay drives over 6 years ago, with OS support from m-soft. 1394 was an attempt to keep the good parts of SCSI protocol, while leaving out as much of the useless stuff as possible (MODE SELECT).

    Fibre-channel is still Real Pricey, for the same reason that SCSI is -- "just because". Or, as the hardware vendors say "harrumph, well, it's all about volume".

    • Throughout the history of ATA, when drive capacities climb towards the addressable limit of the spec, the protocol is kludged by a team of drunken baboons to extend it for another generation

      Yes. We should run out of space in the latest incarnation in roughly 50 or 60 years.

      Unless, of course, you're expecting to implement a single drive with more than 144,115,188,075,855,872 bytes (that's 128 petabytes or 131072 terabytes) anytime soon.

      Yes, previous extentions have been poor. Maxtor got it right for ATAPI-6 which has been adopted by the industry. 48-bit addressing of 512 byte sectors.

  • S-ATA is the Ghetto FC (Score:5, Interesting)

    by Duncan3 ( 10537 ) on Wednesday October 23, 2002 @10:36PM (#4519188) Homepage
    It's real simple, ribbon cables SUCK, they cost more to make then serial so PC makers hate them.

    So, here's how it is...

    Fibre Channel - 2Mb/s(10Mb coming very soon), 126 drives, 10+ mile range, better then SCSI.

    S-ATA - 1.2Mb/s(2.4Mb in 2004), 18" range?, IDE protocols for all your write-only data needs.

    S-ATA is the Ghetto FibreChannel, just like IDE is crappy SCSI, expect similar suckiness and low quality to go with the low price and cheaper cables (to make, to buy they will cost more I'm sure).

    But again, this is all about the creaper cables, since lets face it 95%+ of the machines out there only have one drive anyway.

  • S-ATA exists for one reason... (Score:3, Interesting)

    by Francis Avila ( 603590 ) on Wednesday October 23, 2002 @11:30PM (#4519437)
    ...and one reason only:

    To get rid of those damn ribbon cables.

    Don't believe the marketing hype. SATA isn't about faster speeds, or more advanced features, or any of that crap. S-ATA is about cables.

    IDE is crippleware. At some point in the past there was probably a need for a simpler, less expensive counterpart to scsi for desktop systems, but frankly that need is gone. The price distinction between IDE and SCSI has long been totally artificial. Drive manufacturers make a drive, and then slap on whatever control board they need, IDE or SCSI. Makes no difference to them, except that they get to mark up the SCSI version. Pure marketing: they need to stratisfy their technology so the enterprise guys don't feel like they're sullying their hands with the same tech as those Walmart PC-consumer lusers.

    Frankly I wish SCSI had those neat little connectors (and they soon will, with Serial attached SCSI), and I hate ribbon cables as much as the next guy, but I'm not going to be fooled into thinking this is any real improvement over IDE.

    But even as little as this is, it's long overdue. Those ribbon cables are the enemy of all that is good and just and true in the world.

    Remember folks, SATA is only one letter away from SATAN. Q.E.D. Evil.

  • Serial vs Parallel (Score:3, Insightful)

    by bertok ( 226922 ) on Thursday October 24, 2002 @12:04AM (#4519564)
    I've noticed that the argument for serial over parallel is usually something along the lines of: At higher frequencies, it becomes increasingly difficult to synchronize the signal travelling down multiple parallel conductors, but this is not a problem with serial protocols, so despite having less wires, serial interfaces can be faster thanks to higher signal frequencies.

    This is all fine and good, but why not just treat the wires in a parallel cable as individual serial wires? Sure, if you increase the signal frequency, it becomes next to impossible to guarantee that all the signals arrive at exactly the same time, but I don't see the need for bit-level synchronization. If each wire has its own protocol, its own synchronization, and its own buffers, then as long as there is synchronization at the packet level, there should be no need to worry about synchronizing at the bit level. This would allow both high frequencies, and lots of wires.

  • buyer beware (Score:3, Interesting)

    by frovingslosh ( 582462 ) on Thursday October 24, 2002 @12:06AM (#4519569)
    from the article: and although it wont officially be supported until Microsoft's Longhorn OS

    This seems to say something that I've never seen admitted about serial ATA: that it has DRM built in! If you want to buy hard drives that get to decide what you can and can't store on them, go ahead, but I'm not going to buy into any DRM technology. Extra speed and a smaller cable will not tempt me into doing it; I'll stock up on the last of the regular ATA drives as the serial ATA's replace them.

  • More info (Score:3, Informative)

    by Daniel Rutter ( 126873 ) <dan@dansdata.com> on Thursday October 24, 2002 @12:19AM (#4519618) Homepage
    I wrote a piece [dansdata.com] on this subject a while ago.

    It, um, reads less like a press release than does the Explosive Labs piece :-).

  • A compromise between SCSI and IDE (Score:3, Informative)

    by iankerickson ( 116267 ) on Thursday October 24, 2002 @01:25AM (#4519834) Homepage
    ACARD makes a series of SCSI-IDE bridge cards which connect to the SCSI chain on one side and an ATA hard disk on the other. They have several models, mostly depending on what type of SCSI cabling you have, costing from $50 to $80. They support large ATA disks, the cost of which plus the $70 for the bridge is still cheaper than most SCSI drives. If you don't need the warranty and physical traits of SCSI hard disks, but you want to be able to hook up 6 drives to your PC with only 1 IRQ and IO address or add 60-80 gigs of space for under $200, this might do the trick. They also come in handy for old workstation-era machines, like PowerMacs, SparcStations, or VAXes. The bridge doesn't require any drivers or software to work, since it just tunnels ATAPI and makes the IDE drive look like just another SCSI disk in the chain.

    http://www.acard.com/eng/product/scside.html

    Microland sells them in the US:
    http://www.microlandusa.com/microland/

    Some downsides:
    - The hard disk has to be formatted while cabled to the SCSI-IDE brige. You can't move a drive from a regular IDE controller to the SCSI-IDE bridge without getting geometry errors.
    - The interface is ATAPI only, so not all commands for the device may work. FE, firmware updaters and vendor utilities designed for the hard disk probably won't work the bridge.
    - The utility to update the bridge's firmware is only for DOS/Windows.

    There will probably be LVD-SATA bridges too in the future, if SATA truly catches on.

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