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Serial ATA and Serial SCSI

CmdrTaco posted more than 12 years ago | from the bitsand-bytes-pushing-through-the-pipe dept.

Technology 134

aibrahim writes "In the recent Slashdot article about Serial ATA some people wanted to know where SCSI was going, and if Serial ATA could deal with some higher end workstation and low end server requirements. Apparently it has been decided that Serial ATA 2 (pdf doc) and Serial Attached SCSI are the answers."

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For the CLIT . . . (-1)

News For Turds (580751) | more than 12 years ago | (#3827715)

but dedicated to Fucky and Big Dogs Cock

Re:For the CLIT . . . (-1)

Big Dogs Cock (539391) | more than 12 years ago | (#3827734)

19 fucking seconds instead of 20. I tried.

Oh yeah - best wait a minute or two before pressing submit. Tum te tum te tum te tum te tum te tum. That must be almost it. Time to press .....

Re:For the CLIT . . . (-1)

TheBahxMan (249147) | more than 12 years ago | (#3827742)

G to the mutha phuckin' Oatse.
T to the mutha phukin' Ubgirl.

fo shizzle my nizzle.

yuo aer teh rawx.

Re:For the CLIT . . . (-1)

News For Turds (580751) | more than 12 years ago | (#3827764)

who is jamie?

Slow Down Cowboy!

Slashdot requires you to wait 20 seconds between hitting 'reply' and submitting a comment.

It's been 5 seconds since you hit 'reply'!

Re:For the CLIT . . . (-1)

TheBahxMan (249147) | more than 12 years ago | (#3827777)

jamie is that guy at the bus station who asks to borrow a cup of 3 day old semen so he can brush his teeth.

Because, jamie@igetoffondisneymovies.vg is a fag.

Re:For the CLIT . . . (-1)

News For Turds (580751) | more than 12 years ago | (#3827792)

dude. no. That's not Jamie, that's Jon Katz!

Re:For the CLIT . . . (-1)

TheBahxMan (249147) | more than 12 years ago | (#3827825)

no, jon katz is the guy who trys to get you to sell him you baby's liquified shit (in the diaper) so he can suck it up through a straw.

jamie@imstillabiggerfagthanjonkatz.vg is a fag

Re:For the CLIT . . . (-1, Troll)

Anonymous Coward | more than 12 years ago | (#3827864)

Good One ! [watchtop50.com]

Shut the fuck up (-1, Offtopic)

DojoMojoLojo (590486) | more than 12 years ago | (#3828295)

Showery rain in south clearing. Mostly dry and bright Saturday.

Temperature
Max: 16 C
Min: 12 C

I've just come (-1)

Big Dogs Cock (539391) | more than 12 years ago | (#3827716)

One night upon my motorcycle through the desert sped
And smashed my body so that all my friends thought I was dead
My sister held me close and whispered to my bleeding head
"You are the son of a motherfucker."

One, two, three, four

I shook all night and held her hand
Shock the people, well I'll be damned
Land of plenty, land of fun
To find out I'm Nimrod's son

Oh, bury me far away, please, bury me
The joke has come upon me

In my motorcycle mirror I think about the life I've led
And how my soul's been leaking out the holes where I had bled
My image spoke to me, yes to me it often said
"You are the son of incestuous union."

One, two, three, four

Now, my head is clear
My roof has walls
My daughter's pure
My son is tall
Land of plenty, land of fun
To find out I'm Nimrod's son

Oh, bury me far away, please, bury me
The joke has come upon me


Kerry (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#3827719)

I am from Lehighton, Pennsylvania and I like to stress. Fuck fuck fuck I am angry with my skateboard.

Re:Kerry (-1)

LighthouseJ (453757) | more than 12 years ago | (#3828139)

haha, CKY video with that computer voice.

EP because slashcode is gheyer than jamie (-1)

TheBahxMan (249147) | more than 12 years ago | (#3827727)

for pork soda, news for turds, and the CLiT.

fo shizzle my nizzle, jamie@idontdeservetohavemynamecaptitalized.vg is a fag

Re:EP because slashcode is gheyer than jamie (-1)

News For Turds (580751) | more than 12 years ago | (#3827733)

oh hellZ yeah, bizzzzzzzzzzzznitch

Sounds like fun ... (1)

B3ryllium (571199) | more than 12 years ago | (#3827728)

Now when can I get that 2.5 terabyte RAID1/0 array going?

Can you imagine... (-1, Redundant)

Anonymous Coward | more than 12 years ago | (#3827759)

a beowulf cluster of those?

Re:Can you imagine... (-1, Redundant)

Anonymous Coward | more than 12 years ago | (#3827851)

a beowulf cluster of those?

You know I'm actually starting to find these comments amusing!

Re:Can you imagine... (0, Funny)

Mode0x13 (550144) | more than 12 years ago | (#3828096)

Imagine a beowulf cluster of these posts.

Postercomment compression filter violated. Comment aborted == Add more CRAP!

Re:Sounds like fun ... (1)

HowlinMad (220943) | more than 12 years ago | (#3827760)

screw that, I want raid 5!!!

Re:Sounds like fun ... (-1, Redundant)

Anonymous Coward | more than 12 years ago | (#3827769)

YEAH! Imagine a beowulf cluster of those!

Right now (0)

Anonymous Coward | more than 12 years ago | (#3828157)

Get 4 3ware (or Adaptec) 4 channel ATA raid controllers put em in a box (a really big one :) with 16 160 MB maxtor drives and you will have a 2.5 TB array for the measly sum of ~4000 dollars (performance will be quite good too, these controllers present a SCSI interface to the PC and use mostly hardware for the bookkeeping ... not like the Promise/Highpoint shit).

Copy/Paste a previously published article, anyone? (3, Insightful)

jhoffoss (73895) | more than 12 years ago | (#3827736)

Nearly anything is better than ribbon cables. aibrahim writes "In the recent /. article about Serial ATA some people wanted to know where SCSI was going, and if Serial ATA could deal with some higher end workstation and low end server requirements. Apparently it has been decided that Serial ATA 2 (pdf doc) and Serial Attached SCSI are the answers."
http://slashdot.org/article.pl?sid=02/07/04/153224 =nested=167

Re:Copy/Paste a previously published article, anyo (0, Insightful)

Anonymous Coward | more than 12 years ago | (#3827752)

Dammit. This one will work...
Article Here [slashdot.org]
(Oh yeah, this was posted yesterday... way to read your website, Taco.

Re:Copy/Paste a previously published article, anyo (-1, Flamebait)

Anonymous Coward | more than 12 years ago | (#3827961)

It just goes to show... no one reads Slashdot anymore.

Difference (5, Insightful)

SpatchMonkey (300000) | more than 12 years ago | (#3827737)

The main difference is that Serial ATA will be more readily available first, and will therefore become more popular.

If you look at the Serial SCSI page in the FAQ, note that it is still under development, where motherboards supporting Serial ATA are out now [slashdot.org] .

OSS... (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#3827743)

...is SO innovative. look at xtunes - it's a direct knockoff of iTunes. except it has a shitty UI. it runs on a shitty OS. etc etc etc. seems to be par for the course for Open Sores though because there is little innovation in that area.

mod me down to -1, see if i care. i speak the truth though.

Re:OSS... (-1, Offtopic)

SpatchMonkey (300000) | more than 12 years ago | (#3827773)

Here, you might find yourself getting annoyed with this [dwheeler.com] . Enjoy!

Re:OSS... (2)

SirSlud (67381) | more than 12 years ago | (#3827869)

I dont get it. Are these, like, 40 year old project manager trolls? Or, like, 19 year old scriptkiddie "Nike makes the best shoes, MS makes the best software" trolls?

I wanna know the demographic profile here that for some reason feels threatened by Open Source. Pure curiosity.

Re:OSS... (-1)

TheBahxMan (249147) | more than 12 years ago | (#3827887)

I dont get it. Are these, like, 40 year old project manager trolls? Or, like, 19 year old scriptkiddie "Nike makes the best shoes, MS makes the best software" trolls?

I'd say I'm more of a "you are gay, no sorry, I don't care what you have to say, you aer teh sux and very gay. IF I EVAR SEE YOU I WILL KICK YOUR ASS." trolls.

IF I EVAR SEE YOU I WILL KICK YOUR ASSS!

jamie@ijustwannahavea9inchcockinmyass.vg is a fag

Re:OSS... (-1)

Mode0x13 (550144) | more than 12 years ago | (#3828122)

UR teh sux0r. linux rulez lololololololo

Redundant story (1, Flamebait)

Danta (2241) | more than 12 years ago | (#3827748)

Hey, this exact same story was just published in yesterday's slashback [slashdot.org] .

Wake up, Malda!

MOD PARENT UP (-1)

TheBahxMan (249147) | more than 12 years ago | (#3827756)

I agree with this post.

Re:MOD PARENT UP (-1)

News For Turds (580751) | more than 12 years ago | (#3827814)

I Agree With This Post

Re:MOD PARENT UP (-1)

Mode0x13 (550144) | more than 12 years ago | (#3828135)

I AGREE WITH THIS POST

Re:MOD PARENT UP (0)

Anonymous Coward | more than 12 years ago | (#3828233)

you guys define pathetic

Re:MOD PARENT UP (0)

Anonymous Coward | more than 12 years ago | (#3828330)

bite me

Re:MOD PARENT UP (1)

someonehasmyname (465543) | more than 12 years ago | (#3828653)

I agree with this post . . .

Re:Redundant story (-1, Flamebait)

Anonymous Coward | more than 12 years ago | (#3827815)

Hey, give him a break, in case you didn't notice, it looks like everyone's taking the day off. :)

I doubt it (0, Troll)

Jack Wagner (444727) | more than 12 years ago | (#3827762)

I actually spent a bit of time on the SCSI board of standards back when they were commited towards making great strides in I/O throughput, and they have some real terrific advances that will be released in the next year when their patent's get approved. It's all hush hush and on the QT at the moment and my NDA runs through the end of 2003 so that's all I can say about it.

After briefly looking at the spec for Serial ATA I can see several limitations which will most certainly cause a bottelneck for any I/O simply due to the insane RPM's they require to actually hit their maximum VtR/mg (moving heads [sic] to magnetic resonence ratio). They need to have a look at perhaps doing some embedded hardware hacks which will allow them less resistance in the SCSI channel on the motherboard as opposed to quantum magnetic research. Just my opinion of course and not a reflection of the opinion of my company.

Best Regards,
-Jack

Re:I doubt it (1)

GigsVT (208848) | more than 12 years ago | (#3827801)

They need to have a look at perhaps doing some embedded hardware hacks which will allow them less resistance in the SCSI channel on the motherboard as opposed to quantum magnetic research.

WTF?

A likely story, you sat on the "SCSI board", your consultancy domain name is a spammy squatter domain, you cite some BS ratio, you can't spell "resonance".

I may be making an ass of myself if you really do know what you are talking about, but I call bullshit.

Re:I doubt it (0)

Anonymous Coward | more than 12 years ago | (#3827876)

For what it's worth: Jack was at one of the panels I attended January of last year giving a speak on extending circuit tolerance in solid-state SCSI drive circuitboards (the green board they wire the shiny bits of metal to at the bottom of hard drives these days). He wasn't a speaker, but I recall conversing with him and Rick Sterns from IBM's big iron division. Cool guy; could be making this shit up, but I doubt it.

Re:I doubt it (1)

alienmole (15522) | more than 12 years ago | (#3828321)

You're right. Ignoring the quantum stuff, just the fact that he's complaining about I/O bottlenecks on a bus that's designed to support multiple devices is silly. The whole point is that a single device shouldn't be able to saturate the bus.

Re:I doubt it (-1)

Mode0x13 (550144) | more than 12 years ago | (#3828171)

As a specialist, both in supercalifragilistics and expialidoshous, I congratulate you on your "insight" into these "bottelnecks."

You can find more technical information here. [goatse.cx]

firewire (1, Interesting)

diesel66 (254283) | more than 12 years ago | (#3827763)

a good option to consider. i don't know of any mobo makers that offer it, but it's easy to add on. i think a speed bump to 800 Mbps is around the corner. include the fact that it's hot-swapable, 127 devices or something, etc...

Re:firewire (1)

charnov (183495) | more than 12 years ago | (#3827806)

There aren't any Firewire native drives (that I know of...heh) and Serial-ATA should be cheaper. And, oh, be 1.5Gbs. Maybe now that Apple released all of the licensing surrounding the "standard", we will see it take off like it should have two years ago.

Re:firewire (1)

DansnBear (586007) | more than 12 years ago | (#3827813)

I know of one company that has FireWire on their mobo. . . That would be Apple, the major company in the development of FireWire. heck, they even invented the name FireWire. If it wasn't for them, we would still be running around calling it IEEE 1394.

Re:firewire (0)

Anonymous Coward | more than 12 years ago | (#3828594)


Actually, it was because of Apple that we were calling it IEEE-1394. They owned the name, and wouldn't let anyone else use it with royalty payments. It was only recently that they let up and have allowed the Firewire name to be used by IEEE-1394.

Re:firewire (2, Insightful)

bofkentucky (555107) | more than 12 years ago | (#3827833)

Lets look at it realistically:
  • 800Megabits/s = 100MegaBytes/s, so transfer rate is the same as a standard IDE disk, after the speed bump.
  • What's apple charging for a firewire license these days? Will impact pricing of controllers and drives?
  • You mention hot-swapability, but most ATA drives aren't in hot swap capable enclosures.
  • Is it just the interface or do other things need to change to allow hot swaping (More drive components = more expensive)
  • Are there RAID 1+0 controllers for firewire drives?

Re:firewire (1)

diesel66 (254283) | more than 12 years ago | (#3827901)

ata100 doesn't use it's entire theoretical 100 MBs. also keep in mind that firewire's theoretical limits are 1600 Mbs (not MBs) (i s'pose it's still less than the 1.5 GBs of serial ata :) )

i think the license is $1 per controller/device.

hotswaping is built in. i haven't seen otherwise.

i was just thinking the cabling was cheaper than scsi and ata

Re:firewire (1)

Com2Kid (142006) | more than 12 years ago | (#3827977)

The problem is that most Firewire HDs are just ATA HDs with a Firewire adapter shoved on them, thus they inherent all the limitations of ATA along with any limitations of Firewire. Doh.

Pain in the arse really, and why continue supporting two interfaces on one product if you don't have too?

Firewire is a good overall common denominator specification, but for something physically stable and performance based that also needs a low cost like consumer HDs, a dedicated standard is really best.

Re:firewire (2)

alienmole (15522) | more than 12 years ago | (#3828407)

You're confusing different theoretical limits. The theoretical limit of current Firewire is 400Mbps. The idea is that the Firewire spec allows for future versions of Firewire to reach 1600Mbps, but current Firewire buses aren't even theoretically capable of that. In practice, 400Mbps Firewire doesn't get much above 315Mbps of actual data throughput - consistently slower even than ATA/66, which has been demonstrated in real-world tests.

OTOH, ATA/100 is theoretically capable of 100MB/s, i.e. 800Mbps, in its current incarnation today. You probably won't hit that in practice, not only because of bus limitations, but because 50MB/s is about the max any IDE drive can pump out, so you'd need two drives running continuously at their absolute peak speed in order to saturate the ATA/100 bus.

Sheesh! (4, Funny)

Mike Hicks (244) | more than 12 years ago | (#3827766)

...and just as I'm building my fibre channel array for my home computer :-p

Where are the drives? (2, Interesting)

charnov (183495) | more than 12 years ago | (#3827775)

Okay...I have a SATA equipped mobo on order which comes in in two weeks. What I want to know is: where are the hard drives? And no, I don't mean the drives that are standard ATA100 that have converters. I mean Seagates native SATA drives. They demoed supposed "production" pieces back in Fenruary.

Re:Where are the drives? (-1)

TheBahxMan (249147) | more than 12 years ago | (#3827794)

Did jamie tell you that when you were sucking him off in Fenruary? Or was that when he had a tire iron stuck up his ass and you offered to remove it with your teeth.

jamie@iwishiwasntadirtyexican.vg is fag

Re:Where are the drives? (2, Informative)

bjschrock (557973) | more than 12 years ago | (#3827845)

The Segate Baracudda ATA V, Serial ATA version is going to be released "this fall" according to a press release I read somewhere. It has a 8MB cache and comes in sizes up to 120GB.

Evil Drives (4, Funny)

Blahbbs (587167) | more than 12 years ago | (#3828114)

So when will someone come out with a Serial ATA Network device?

Yup, a SATAN Device (tm).

...boo...hiss....

Re:Evil Drives (-1)

xdfgf (460453) | more than 12 years ago | (#3828317)

Hail Satan!

The Year is One!

The Dark Lord Cometh!

Re:Where are the drives? (1)

alienmole (15522) | more than 12 years ago | (#3828121)

Welcome to early adopterhood! Sounds like you need to wait for Seagate's drives in the fall, assuming they release on time.

You can bet the first SATA drives are going to be quite a bit more expensive than an equivalent capacity ATA100, too.

Time to start shopping for converted drives?

Re:Where are the drives? (2)

MrResistor (120588) | more than 12 years ago | (#3829395)

You can bet the first SATA drives are going to be quite a bit more expensive than an equivalent capacity ATA100, too.

Not according to Seagate. I wish I could remember where I read that, but it was fairly recent.

Serial SCSI is neat. (4, Insightful)

Sheetrock (152993) | more than 12 years ago | (#3827780)

I've read a couple of brochures on this technology (we're looking at high-bandwidth high-availability file clusters for our hybrid AS/400-Solaris data warehousing) and it looks extremely promising.

Basically, they're extending parallel SCSI technology to address next generation I/O and direct attach storage requirements. It uses the (proven) interface from Serial ATA to avoid an unnecessarily proprietary interface and the costs that usually entails. The naming is unfortunate, because one usually thinks of parallel (side-by-side) as being faster than serial (one after the other) when the technology allows you to combine the two tactics much like in LANs. This is the technology that will enable a new generation of dense devices, such as small form factor hard drives, whereas Parallel SCSI can't because of cabling and voltage issues.

So depending on the pricing of the technology when it hits the shelves/junk mail catalogs, we're going to take a serious look at it. Does anybody have any prototype benchmarks?

I AGREE WITH THIS POST (-1)

TheBahxMan (249147) | more than 12 years ago | (#3827859)

because I'm NOT a banana.

jamie@iwishiwasasleetastweek.vg eats out downies.

Re:I AGREE WITH THIS POST (-1)

Mode0x13 (550144) | more than 12 years ago | (#3828184)

ur teh rawx

Re:Serial SCSI is neat. (0)

Anonymous Coward | more than 12 years ago | (#3829247)

The 1930s called, they want their lingo back :)

Serial SCSI (0)

Anonymous Coward | more than 12 years ago | (#3827793)

... It's called Firewire and within the next three years it'll be used to link up hard drives, networking and peripherals, according to Apple in 1996, unforunately in that time plain old ATA, Ethernet and USB have seen it off.

Serial ATA v. SAS (1)

bjschrock (557973) | more than 12 years ago | (#3827818)

As the Serial ATA PDF points out:
Serial ATA is also expected to be a viable alternative for cost-sensitive entry-level and mid-range server and network storage applications. ... some of the advanced features of the SCSI protocol were not implemented.

So for some or most high-end storage applications, SAS and Fibre Channel will still beat out Serial ATA because you can do a lot more things with the SCSI protocol. Another big advantage of SCSI (in either SAS or Fibre Channel form) is the advantage of many targets to one initiator, or multiple initiators, with current parallel SCSI it's 15/1 and for Fibre Channel it's over 100 to 1 (I forgot the exact number). Multiple initiators aren't supported in Serial ATA II until phase 2, and Ultra 320 SCSI is already faster than the projected 300MBps of phase 2.

Re:Serial ATA v. SAS (1)

charnov (183495) | more than 12 years ago | (#3827836)

Ultra320 SCSI is also INSANELY expensive...along with fibre channel.

Re:Serial ATA v. SAS (1)

FueledByRamen (581784) | more than 12 years ago | (#3828313)

I beg to differ on this. Ultra320 SCSI may be insanely expensive; I've never used it, so I wouldn't know. However, Fibre Channel is not insanely expensive. If you look on eBay under a certain seller , 9.1gb 10,000RPM Seagate FC drives go for $9 each. A Fibre Channel interface card that sticks onto these drives and attaches them to the "loop," while normally costing $50 or more on eBay, I make for about $9 in parts each (including PCB). Cabling is simple - CAT5[e] works perfectly. The Fibre Channel HBA isn't too cheap - around $100 (this is the card you stick in your computer) - but I bought a pair of HP Copper HBAs for $20 each, shipped.

Re:Serial ATA v. SAS (1)

Com2Kid (142006) | more than 12 years ago | (#3827998)

I read someplace that ATA is just SCSI with all the goodies striped out to begin with, so this just sounds like a continuation of that pattern. ::shrugs:: Makes sense really, look at what the top performer is and how it works, and then take out all the very high end stuff that is not likely to be used with it in order to simplify it down and reduce costs, make it a bit more user friendly (at the cost of a bit of performance), and release it as a consumer spec.

Re:Serial ATA v. SAS (2, Interesting)

iKitty (590509) | more than 12 years ago | (#3828080)

Your performance assumptions are flawed. U320 SCSI allows 320MB/sec for the entire SHARED SCSI BUS (15 drives). S-ATA gives you 150MB/sec to EACH drive; the SATA controllers support a Direct Port Access (DPA) mode that allows DMA transactions to proceed simultaneously to all drives. With the new Seagate and WD drives having the larger 8MB cache in each drive we will see decent per drive performance and in large drive arrays (>8 drives) the performance should beat the pants off of SCSI.

Re:Serial ATA v. SAS (1)

siliconwafer (446697) | more than 12 years ago | (#3829132)

Very informative post, surely it should be modded higher than 2. Anyways, (being an idiot and not reading the article) does anyone know how many SATA devices can be attached to a single controller? Is it 2 like regular ATA?

Re:Serial ATA v. SAS (0)

Anonymous Coward | more than 12 years ago | (#3829227)

so serial ata is faster than u320 scsi because the controller has more channels? do you realise that this makes no sense?

S-ATA will dominate NAS (0)

Anonymous Coward | more than 12 years ago | (#3828597)

The higher bandwith of Ultra-320 is not meant for a single drive, if you were to construct a system like that cost would go out of control. 150 MB/s per drive is plenty for any use, including high end servers.

If you have dedicated hardware talking to the drives things as command queing are totally meaningless (because it can just keep a queu itself and respond to interrupts as soon as they occur). So for big RAID/NAS with dedicated hardware the only thing SCSI has over S-ATA is the fact that the access time can be lower for single SCSI drives and sometimes higher reliability but that has fuck all to do with the protocol. The higher the number of drives the lower the average access time though, so with lots of drives this is not as big an issue as you might think, and you can just factor reliability of drives into the redundancy of your array ...

Areas will remain where SCSI rules supreme, but as long as the price differential exist they will get smaller and smaller. As clusters have shown, price always matters.

I believe.. (2, Interesting)

iONiUM (530420) | more than 12 years ago | (#3827822)

I believe the general conception that SCSI is too expensive for the home user is going to make it hard for SCSI to pick up now. Although SCSI is much faster (and better for business in my opinion), I think IDE will continue to rule with it's slower perfomance and cheaper prices the home market. Quite a shame though, IDE seems to always be so slow when compared to the incredibly fast SCSI drives out... but then again, the size of IDE w/ current prices means you can get a huge hard drive for relatively cheap, which is almost impossible with SCSI.

Re:I believe.. (2)

Courageous (228506) | more than 12 years ago | (#3828191)

Well, you do know, don't you, that there is no reason why Seagate can't be selling those 15,000 RPM Cheetahs with an IDE interface if they wanted to, right? The SCSI bus issue doesn't significantly impact the drive speed in any way. It's a _BUS_.

C//

Internal firewire? (1, Interesting)

Anonymous Coward | more than 12 years ago | (#3827839)

While this is not important (hence my score:0 AC post) i would just like to ask a quick question related to this story topic i have been wondering about, as there tend to be many people on slashdot with more knowledge than i, so maybe someone will have an answer.

Does anyone know if there have been any steps anywhere in the Industry toward the eventual offering of internal hard drives that use FireWire? Would that not be cost efficient?

Re:Internal firewire? (3, Informative)

alienmole (15522) | more than 12 years ago | (#3828260)

Current Firewire is half the bandwidth of ATA/100. Theoretically, Firewire can be saturated by a single fast disk, so for internal Firewire you'd want a separate Firewire channel on the motherboard for each disk - but Firewire was really intended to be a serial bus which supports multiple devices. That's why in its current form, Firewire is more appropriate for connecting devices like video recorders, or hooking up a single external drive for data portability, than for internal drives.

from the serial scsi FAQ (0)

Anonymous Coward | more than 12 years ago | (#3827900)

# links -dump http://www.serialattachedscsi.com/faq/faq.html | perl -e 's/\ /\n/g' -p | grep leverag | wc -l
4
#

Four occurances of leverage or leveraging is too many in one FAQ. I don't trust them. I'm buying serial ATA.

Drop ATA (0)

Anonymous Coward | more than 12 years ago | (#3827935)

Lets just drop ATA. It is an out of date spec. Lets just all buy SCSI, it will go down in price and will be as cheap as ATA soon enough.

just like the RAMBUS story (2, Interesting)

lingqi (577227) | more than 12 years ago | (#3827949)

remember back when RAMBUS said: we will provide an architecture with very narrow bus but extremely high speed to make up for it? (the *original* RAMBUS specs) -- beside the royalties and whatnot -- it actually (technology discussion only) had merits in that the PCB design was greatly simplified because of less crosstalk, easier routing, etc etc.

and then, people demanded more bandwidth... so now we have double / quad pumped RAMBUS channels -- in the end (today) it's back to 64-bit data-bus *anyhow*... except with an architecture that's not designed for parallel operation.

do anybody see some parallel (ha!) here?

i am guessing (or, predicting) that serial ATA / SCSI will go the same route. i really hope that it won't -- because if it did, our lives will all be kinda rough -- but it probabbly will.

sigh...

Re:just like the RAMBUS story (2, Informative)

jamesbulman (103594) | more than 12 years ago | (#3828025)

Double / Quad pumped rambus channels refer to the frequency at which they are being driven, not the number of traces laid down. Rambus is as narrow as it has ever been.

nope (1)

lingqi (577227) | more than 12 years ago | (#3828160)

sorry for the mis-use of language -- what i am refering to is "dual-channel" RDRAM.

it was implemented on intel's i850 (? -- don't remember so well anymore) -- and required two modules to be installed simultaneously.

now that DDR / DDR II is catching up to RDRAM in terms of bandwidth, RAMBUS decided that all the "high performance" RDRAM modules will be "dual channel on a single chip" (which, btw, is 32 bit); now you will say -- this is still small -- but remember that originally RAMBUS can be used with only 8-bit bus width (somebody correct me if i got this wrong); and on the horizon quad-channel (64-bit) RAMBUS is looking at ya. guess how wide is the DDR / SDRAM bus? 64 bits too? ditto.

RDRAM is double-pumped (i do not believe it is a technical term, btw) -- data comes on both pos and neg edge of clock. there is no *real* quad-pumped memory; QDR-RAM is still only double-pumped except both I and O can operate simultaneously. only used in SRAMs anyway. (FYI)

Re:nope (2)

Fulcrum of Evil (560260) | more than 12 years ago | (#3828459)

what i am refering to is "dual-channel" RDRAM.

The thing to remember there is that you don't have to synchronize the channels - they go as fast as they go. Multi-channel interleaved ram is a pretty easy way to speed up access, but it costs more (of course)

Re:just like the RAMBUS story (3, Informative)

cheezedawg (413482) | more than 12 years ago | (#3828048)

Ethernet has had no problems scaling to higher bandwith while maintaining its serial "bus". Serial ATA is a packetized interface that is more similar to ethernet than RAMBUS. They already have 600 MB/sec SATA on the roadmap.

i think you are getting confused (1)

lingqi (577227) | more than 12 years ago | (#3828275)

ETHERNET is a protocol; i think what you are really saying is that unshielded twisted pair was able to bump up in speed progressively.

i am not concered with the ATA protocol, in this case -- rather the amount of signals moved through the cables connecting the drive to your board;

even the venerable UTP can only get to 1Gbit and no more; ethernet lives on, 10Gbit ethernet standard is here, but guess what, fibre only.

same with ATA; you can only move so much signal (electrically) through wires. or, signals of so high a frequency; in this case, for a specific type of cable, there in a maximum amount of information that can travel through it. (unless you go out of your way to shield them, etc etc -- but a nicely shielded cable will cost you ~1500 dollars -- most high freq oscilloscope probes uses them, btw.) anyhow; serial ATA tries to bump up speed with a serial interface -- mainly to simplify MB design considerations -- less traces, narrower bus, etc; but since each strand in your cable will only go so far -- i am betting that eventually (without resorting to optical connections) even serial ATA, under the demand of higher throughput either by the market or by their (un)realistic roadmap -- start to double / quadruple the bus width. to me this is just silly -- because the benefit this offered is going away! MB designers will again have to fudge with wide busses and connections.

we might as well just keep on using parallel ATA but boost the signal freq incrementally, since it will get us to the same place in a few years anyway, without all these incremental MBs using different sized busses that's not compatible with different generation drives.

by the way -- PCI bus can only push 133MB anyhow -- anything beyond that is silly

Re:i think you are getting confused (0)

Anonymous Coward | more than 12 years ago | (#3828521)

the venerable UTP can only get to 1Gbit and no more

But didn't they say the same thing when it reached 10Mb/s, claiming that's the limit and if you want any faster you'll have to go fiber?

Re:i think you are getting confused (2)

cheezedawg (413482) | more than 12 years ago | (#3828668)

No, my point was they didn't have to add more signals to increase the speed of ethernet, and they probably won't have to with SATA either. Look at all of the hot technologies now: USB(2), firewire, 3GIO, SATA, and Serian SCSI. They are all serial interfaces.

we might as well just keep on using parallel ATA but boost the signal freq incrementally, since it will get us to the same place in a few years anyway

One of the biggest reasons for developing SATA was that parallel ATA is pretty much maxed out at 133 right now- we can't just "boost the signal freq" any more. Plus, parallel ATA is based on TTL signaling, and that requires the integrated circuits to tolerate +5V input signals. This is getting harder and harder to support with the modern manufacturing processes of the chip. And as you pointed out, the fewer signals also has the benefit of simplified design and reduced the cost of the chips.

by the way -- PCI bus can only push 133MB anyhow -- anything beyond that is silly

I hope you weren't serious about that.
#1. If PCI is becoming the bottleneck, then we will move past it. In fact, we already are. PCI's replacement (3GIO) is already in development (actually I think they changed the name to PCI Express- kind of dumb if you ask me).
#2. Integrated SATA implementations will not be on the PCI bus, so they will not be limited to the bandwidth of the bus. They will only be limited by the upstream bandwidth between the southbridge and northbridge chipsets (on current Intel desktop chipsets, this is 266 MB/sec with plans to increase to 533 MB/sec soon- AMD's Hypertransport is also more than adequate for SATA)

Re:i think you are getting confused (1)

lingqi (577227) | more than 12 years ago | (#3828902)

USB(2), firewire, 3GIO, SATA, and Serian SCSI. They are all serial interfaces.

yes... look at a firewire cable; shielded twisted pair; the thing is, when you cram more and more signals through a cable, the cable itself gets quite pricy, so you are offloading design costs of the motherboard onto the quality control of cabelling, which i see no point in. high quality cables (shielded) cannot be bent too much because that will cause variations locally in the dielectric, screwing up your signal. and frankly, cables are much more likely to get bent / messed up than a trace in the PCB, so i rather see technology that's not very dependent on the cable quality / condition.

parallel ATA is pretty much maxed out at 133 right now

i am not denying this fact -- but at the mean time; i believe my argument still stands; what i do not like is the fact that suddenly, when moving to a new architecture, we decide that "we can do this with a narrow bus". i don't believe it. it is great and fine that you can reach the next step in your road map with only an 8-bit bus, but that does not mean you should do it. because i believe eventually the bus size will double and again. i hate to see that level of bs people will have to put up with. say i have a old MB when mainstream serial ATAs now have twice the bus width as when my MB was designed. how much are you willing to bet that it won't work then? USB and firewire will reach their maximum capacity (cable-wise) in the future, and when that happens, i bet you a dollar to a donut that the spec will start calling for wider busses on those too. but unlike specs that maintain their bus width, interoperability will be severly limited.

I hope you weren't serious about that.

i was about half serious -- and yes -- i know that SATA will be intergrated into the chipset directly, with it's own channels out. but wait a sec here... how does that simplify MB design again? you are saying i need a few more high freq traces going into the chipset, which is already crammed full of traces to the memory, AGP, southbridge, processor, etc? I would much more rather see a wider adoption of an evolutiona to the outdated PCI bus, and have things hang off those -- than have these new and fancy crap that gets crammed into the chipset. PCI, btw, *is* a bottleneck because any SATA adapter cards will hang off the PCI bus (say i want 8 drives for my system)... i wish the industry puts forth half as much momentum behind say, PCI64's adoption than SATA, etc.

Re:i think you are getting confused (2)

cheezedawg (413482) | more than 12 years ago | (#3829219)

FWIW, the major OEM's have been clamoring for SATA because the SATA cables are cheaper than PATA ribbon cables.

And the 70+ companies in the SATA Working Group, the PCI-Sig (for 3GIO), and the USB and Firewire designers disagree with your assessment of the scalability of these serial interfaces.

And replacing the 26 (or whatever) signal pins that are currently integrated into the southbridge chipset for parallel ATA with the 4 signals for SATA certainly does simplify MB design.

Re:just like the RAMBUS story (0)

Anonymous Coward | more than 12 years ago | (#3828051)

Actually, you are dead on target here.

One of the main limitations of sATA is that it is point to point. This means one cable per device. SAS will be similar, but out the door it will have the ability to use Hubs, where sATA won't until a later generation.

This means serial = more individual wires. So, it makes a lot more senese for IDE, where the standard configuration is only one or two devices today, and the cables are much smaller.

SERIAL (2D) versus VOLUME (3D) (0)

geekster_2000 (580578) | more than 12 years ago | (#3827974)

slow versus fast

http://colossalstorage.net/colossal.htm

I heard (4, Insightful)

Apreche (239272) | more than 12 years ago | (#3828223)

that serial ATA, while being very fast and much better than what I've got now, will have DRM built in. Is this true? Should I not get serial ATA in my next system because of it? Anyone got any links pertaining to this issue?

ATA/SCSI distinction (3, Interesting)

XNormal (8617) | more than 12 years ago | (#3828500)

With current silicon integration levels there is no real reason why SCSI should be more expensive than ATA. They could have just merged them and perhaps emulated braindead ATA on top of SCSI to keep compatibility or something if anyone really wants to.

I'm pretty sure the only reason they keep the difference is to be able to charge more from people building servers. It's purely a marketing and price positioning decision.

Re:ATA/SCSI distinction (0)

Anonymous Coward | more than 12 years ago | (#3828620)

I agree. SCSI drives/technology has always been about creating a class system in the industry to squeeze more money out of peoples pockets. There is no engineering reason SCSI drives should cost more. These /. SCSI vs. ATA debates are a perfect example.

I think we all agree here that SCSI is a better engineered interface storage solution, but I for one am not willing to pay twice the price just so I can call myself some follow the Jone's superiority freak.

In many ways I'm glad that SATA may remove the class system and level the playing field for everyone.

SCSI...time to die.

Aha! So I Serial Scsi is Good? Go IBM.. hmmm (0)

Anonymous Coward | more than 12 years ago | (#3828574)

So when did IBM SSA (serial scsi architecture) which has done 160megabytes/s for the last few years suddenly become mainstream??

It didn't

Someone else has to 'reinvent' it. At least
the acronyn is almost the same. SAS vs SSA...

Hey why not! Reinventing old technology for the ignorant masses has always been Microsoft's Cash Cow.

Re:Aha! So I Serial Scsi is Good? Go IBM.. hmmm (0)

chez69 (135760) | more than 12 years ago | (#3828638)

actually, SSA in IBM terms is serial storage architecture.

back to the old days? (1)

PalmKiller (174161) | more than 12 years ago | (#3828578)

So the serialized interfaces like on the old atari and commodore computers were ahead of their time, granted they were slow?

Re:back to the old days? (0)

Anonymous Coward | more than 12 years ago | (#3828711)

>> So the serialized interfaces like on the old atari and commodore computers were ahead of their time, granted they were slow?

Not quite... ever changed the device ID on a Commodore 1541 floppy drive? Lets see... you power on the drives one at a time (with DeviceID #8 powered on last of course), and for each one you power on, run a complicated PEEK/POKE sequence to set the device ID prior to powering on the next drive in the sequence.

Alternately you can follow the instructions in the official drive manual to permanently set the ID by disassembling the monstrosity and *cut* circuit traces on the PCB and/or add a drop of solder to give you the desired device ID.

Ahh... memories.

So? (5, Interesting)

gerardrj (207690) | more than 12 years ago | (#3829002)


They still don't say that serial ATA will support more than two devices per channel. In fact they say it will be software compatible with ATA in its current form, suggesting it continues the master/slave relationship.

Today's drive media can only reach 40MB/s reading from the platters for short bursts, if their lucky. Normally they'll read/write about 20MB/s. What's the point of another boost in speed of ATA (to the suggested 150MB/s) when you will only ever be able to use 80MB/s of that. Oh, that's right... the ignorant users need bigger numbers on their cardboard boxes to show off to the neighbors.

Does anyone have any information on a HD soon to be released that will offer a quantum leap of read-from-meadia performance to something like 75MB/s? That's more than triple the current read-from-meadia speeds, and they seem to only ever increase the speeds by about 1-2MB/s each year.

SCSI makes sense having very high bus bandwidth, as you can connect quite a few devices and use the connect/disconnect to send simultaneous reads/writes to multiple devices. In that scheme, you can keep most of your drives operating at the same time. Of course Apple has shown that at least for a small RAID, multiple independent ATA channels are just as fast and lower cost than a single SCSI channel. I persoanally have a difficult time thinking that multi-ATA design would scale well to a 32 drive RAID, where a dual channel SCSI would shine.

Serial Attached SCSI, redundant technology? (0)

Anonymous Coward | more than 12 years ago | (#3829173)

Shoot me if I'm wrong, but isn't Small Computer Serial Interface (SCSI) ALREADY serial?
SCSI-1 was 8bit serial, SCSI-1 wide 16bit serial, SCSI-2 16bit serial SCSI-2wide 32bit serial, etc. but all serial. each bit channel independant of each other. Am I missing something?
I can understand it if they're just trying to get a small and manageable connector, but otherwise, considering the companies listed as members, they should know this already!

Serial SCSI? (2, Insightful)

ghopper (580600) | more than 12 years ago | (#3829198)

Isn't that called Firewire?

SCSI vs Firewire [adaptec.com]

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