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Serial SCSI Standard Coming Soon

michael posted more than 11 years ago | from the scuzzy-wuzzy dept.

Hardware 328

rchatterjee writes "SCSI is very close to joining ATA in leaving a parallel interface design behind in favor of serial one. Serial attached SCSI, as the standard will be known, is expected to be ratified sometime in the second quarter of this year according to this article at Computerworld. Hard drive manufacturers Seagate and Maxtor have already said that they will have drives conforming to the new standard shipping by the end of the year. The new standard will shatter the current SCSI throughput limit of 320 megabit/sec with a starting maximum throughput of 3 gigabit/sec. But before this thread turns into a SCSI fanboy vs. ATA fanboy flame war this other article states that Serial Attached SCSI will be compatible with SATA drives so you can have the best of both worlds."

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328 comments

Coming soon to a SCSI market near you! (-1, Flamebait)

Anonymous Coward | more than 11 years ago | (#5472992)

Serial ATA. Why bother with Adaptec junk?

Attention all trolls (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5472996)

Your assistance is needed at once in comp.os.linux.advocacy. The linnuts are out of control!!!

SASCSI (3, Insightful)

epyT-R (613989) | more than 11 years ago | (#5472998)

Well, at least we can get rid of those hard-to-route ribbon cables. That alone is worth the switch, IMHO.

Re:SASCSI (2, Interesting)

chrisseaton (573490) | more than 11 years ago | (#5473007)

I've always wondered, why are they ribbions? Why not simply roll the ribbons up into cables? Can anyone enlighten me?

Re:SASCSI (1)

Aliencow (653119) | more than 11 years ago | (#5473018)

ThinkGeek has some non-ribbon IDE cables... But I'm thinking it's probably due to interference or crosstalk between the cables..

Re:SASCSI (1)

grishnav (522003) | more than 11 years ago | (#5473040)

IIRC, one of the reason to use non-ribbon cables is to reduce the crosstalk, so long as they aren't wound like a coil (but rather braided).

Re:SASCSI (1)

epyT-R (613989) | more than 11 years ago | (#5473020)

I'm not sure, but it probably has to do with the inductance effects on the longer cables.

Re:SASCSI (2, Interesting)

sirsex (550329) | more than 11 years ago | (#5473047)

I believe it is due to the inductive crosstalk between the channels. With ribbons, only the two adjacent wies are a major concern, while a cable would have many more conductors in close proximity. The interfence will add linearly with each noise source

Re:SASCSI (5, Informative)

Ryan Amos (16972) | more than 11 years ago | (#5473058)

To reduce crosstalk between the wires so that you can run at faster speeds. Indeed, the "rounded" IDE cables often reduce performance by 5% or so. We're getting better at data throughput though, so we can use serial technologies and actually get faster transfer rates. Good riddance to ribbon cables :P

Re:SASCSI (5, Informative)

shepd (155729) | more than 11 years ago | (#5473067)

>Why not simply roll the ribbons up into cables?

Impedance, crosstalk (mentioned) and price.

It takes seconds to crimp a ribbon cable. Cheap and easy. You can even do it yourself!

Taking a bunch of twisted pair wires (which is what would be required to keep the impedance and crosstalk bearable) and soldering them onto connectors individually takes a lot more effort, and therefore costs more.

Not to mention fabbing individual strands of insulated wire and twisting them together costs more than running 5 wires parallel to each other and simply coating them all at the same time with PVC.

You can... (1)

Kjella (173770) | more than 11 years ago | (#5473072)

I have some rounded cables. But:

1) The connectors must still be huge
2) As a consequence, the connector -> cable area is big.
3) There's so many connectors, the cable is big and inflexible.

Basicly, I couldn't fit the cables the way I wanted to have the disks, because they were so inflexible they collided with my GF4. So I had to rearrange the disks instead. With ribbon cables, it'd be much more of a mess but it would have worked. SerialATA is much better designed for this.

Kjella

Re:SASCSI (2, Interesting)

Waffle Iron (339739) | more than 11 years ago | (#5473130)

Another major advantage of ribbon cables is that they are dirt cheap. They can be stamped out in one step without handling the individual wires. You can also attach connectors to all ~50 wires just by shoving the sharp teeth through the ribbon in one motion. No soldering or advanced tools required.

first post first post!!! (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5472999)

Yaaaaa!!

Re:first post first post!!! (0)

Anonymous Coward | more than 11 years ago | (#5473008)

Moron! Moron! Yaaaaa!! Nowhere even fucking close!

What is it about... (0)

Anonymous Coward | more than 11 years ago | (#5473258)

FAILURE that begets you to FAIL IT?

s/megabit/megabyte/ (-1, Redundant)

Anonymous Coward | more than 11 years ago | (#5473000)


I think Ultra320 SCSI can keep up with GigE. ;)

evil technology! (5, Funny)

Anonymous Coward | more than 11 years ago | (#5473002)

Serial ATA Network = SATAN

Mbit != MByte (0, Redundant)

tage (14671) | more than 11 years ago | (#5473006)

That should be "320 MByte/s" and "3 GByte/s", shouldn't it?

Re:Mbit != MByte (2, Informative)

Anonymous Coward | more than 11 years ago | (#5473026)

Actually, that's 320 Megabytes per second for Ultra 320 SCSI and 3 Gigabit per second (approx 375 Megabytes per second) for Serial Attached SCSI

Technical Data (-1, Offtopic)

Anonymous Coward | more than 11 years ago | (#5473010)

This disc was recorded on an Ampex stereo tape recorder from 10 CPS bottom to
30,000 CPS top; transferred to disc with Neumann lathe
plus a Teldec cutting head, and utilizes the standard 'RIAA' playback curve. This disc was pressed
from the finest virgin vinyl, in a process that removes surface noise and distortion. A
microgroove-stereo pickup with a .0007 tip radius+.0001 is recommended for finest results,
with a stylus weight of not more than 4 grams.


Handle this disc with great care, especially avoiding touching the playing surface with
fingers (skin oils damage the vinyl). Use a soft damp
cloth to clean the disc, and store it carefully in this jacket at moderate temperature. With proper
care this high fidelity stereophonic disc should last indefinitely.

Re:Technical Data (0)

Anonymous Coward | more than 11 years ago | (#5473033)


mmmm dubplates, can you smell crayons ?

Heck of a way to hype the Harper Valley PTA LP (0, Offtopic)

tjstork (137384) | more than 11 years ago | (#5473052)

Now of course, we carefully use super sampled DVD audio to get Britney Spears. If only musicianship advanced as fast as technology!

Bits? Bytes? Whatever! (1, Informative)

Anonymous Coward | more than 11 years ago | (#5473011)

The current parallel SCSI is 320 megaBYTEs per second, which is 2.56 gigaBITs per second.

bits vs. bytes (5, Informative)

David Jao (2759) | more than 11 years ago | (#5473013)

Guys (meaning submittors and editors), the current version of SCSI delivers 320 megabytes [scsita.org] per second of interface transfer rate, not megabits.

320 megabytes is about 2.5 gigabits ... which is a lot closer to 3 gigabits than the erroneous 320 megabits figure.

Re:bits vs. bytes (2, Insightful)

g4dget (579145) | more than 11 years ago | (#5473187)

Yeah, but what drive actually delivers 320 Mbytes/second? As long as the connection between the controller and each drive can keep up with the drive, the connection is fast enough.

Of course, a really fast connection may allow you to daisy chain and still get almost full transfer rates from each drive, but that's not really such a big deal, in particular when the cables are as small as they are for serial connections.

Re:bits vs. bytes (3, Insightful)

Daniel Phillips (238627) | more than 11 years ago | (#5473239)

Yeah, but what drive actually delivers 320 Mbytes/second? As long as the connection between the controller and each drive can keep up with the drive, the connection is fast enough.

Scsi is a bus. I have a box here with 5x10K drives, at 49 MB/s each, easily able to saturate its ultra 160 bus. These days, that box is nothing special.

SCSI = ... (4, Funny)

product byproduct (628318) | more than 11 years ago | (#5473015)

If I understand the title correctly, SCSI = Standard Coming Soon Interface?

Re:SCSI = ... (1)

jspoon (585173) | more than 11 years ago | (#5473042)

Small Computer Something Interface (I know you were joking, this just leapt to my mind)

Re:SCSI = ... (0)

Anonymous Coward | more than 11 years ago | (#5473070)

Small computer Systems Interface

SCSI? (1)

The Notorious ASP (628859) | more than 11 years ago | (#5473263)

SCSI = Small Computer Systems Interface.

If it had been up to me, I would have moved the vowel sound and called it "Sexy" instead of "Scuzzy"

Re:SCSI = ... (4, Funny)

Anonvmous Coward (589068) | more than 11 years ago | (#5473085)

"If I understand the title correctly, SCSI = Standard Coming Soon Interface?"

I think it stands for

Some Can't Stand IDE

Nitpicking... (0)

Anonymous Coward | more than 11 years ago | (#5473016)

Article says: "...current SCSI throughput limit of 320 megabit/sec...", that should be 320 megabyte/sec...320 mbit/s would (when you've taken protocol latency etc into consideration) translate to something like 30 megabyte/second...not very impressive =)

Serial SCSI Drives (1)

GeXX (449863) | more than 11 years ago | (#5473021)

Now only if we can get the drive to read or write to the platters @ 3Gbit/sec. Also, is that suppost to be 320Mbit/sec or 320Mbyte/sec for the current SCSI throughput, because if my math is right, 3Gbit/sec is 380Mbyte/sec which os what 60MB faster / sec then current scsi drives.

You know really.. (0)

Anonymous Coward | more than 11 years ago | (#5473024)



"the best thing about standards is there are so many to choose from"

could never be a more truer statement

why not call it something else instead of another scsi interface ?

scsi 1 2 3 4 wide av ? when does it stop ? cos the creativity in naming schemes seems to of stopped years ago

How parallel will it be? (3, Interesting)

tjstork (137384) | more than 11 years ago | (#5473025)

Will this new standard be able to do things in parallel the way SCSI can? Will I turn my server into a PC like box that seemingly pauses every time the swap file gets touched?

Ok, So I've noticed a couple of corrections. (5, Insightful)

taliver (174409) | more than 11 years ago | (#5473027)

If the article meant to say 3GBytes, then how in the world will the PCI *at 64bits and 133MHz, it's 1 GB/sec transfer) bus keep up? Or even RAMBUS memory, which, here [kingston.com] says it has a bandwidth of 4.2GB/sec. (So, kinda means you couldn't have more than one SCSI system at a time and get full bandwidth from both.) Now, if you may have to have memory banks for each SCSI component... ick.

Re:Ok, So I've noticed a couple of corrections. (2, Informative)

Zebra_X (13249) | more than 11 years ago | (#5473121)

PCI Plus proposed by Intel is promising 2GB/sec dedicated channel per device on the PCI Plus bus.... this doesn't fully meet the needs of the drives but is certainly a step in the right direction.

Re:Ok, So I've noticed a couple of corrections. (1)

lederhosen (612610) | more than 11 years ago | (#5473122)

DRAM modules (or the mem-controller) does not
lie on the pci-buss. It lies on the northbridge
or on the cpu itself (like hammer). Nothing is
forcing you to place the SCSI controller on the
pci-buss.

Re:Ok, So I've noticed a couple of corrections. (1)

taliver (174409) | more than 11 years ago | (#5473163)

Fine, but if it's not going to be on the PCI bus nor on the memory bus, where do you propose to put it?

Now, about 2-3 years ago, there was the infiny-band (sp?) solution, where this SCSI device could simply feed any number of processors and memory units on a huge 30Gb/sec shared bus structure. That has since died.

But that still leaves me with the question of where you plug this puppy into.

Re:Ok, So I've noticed a couple of corrections. (1)

lederhosen (612610) | more than 11 years ago | (#5473176)

On a hyper-transport link or on the northbridge
like the agp buss.

Re:Ok, So I've noticed a couple of corrections. (1)

taliver (174409) | more than 11 years ago | (#5473267)

With a 533MHz front side bus, and assuming a 128 bit wide structure (unrealistic), you're just at 8GB/sec. And theoretically you'd want to have something else beside disks on this system-- maybe memory and video? Maybe a network?

Re:Ok, So I've noticed a couple of corrections. (3, Informative)

torre (620087) | more than 11 years ago | (#5473175)

With PCI-X 1066 [pcisig.com] 8.6GB/s bus tranfers are possible so that should be too much of a problem. Also, the InfiniBand [infinibandta.org] aims to solve that problem. One can see that 6GB bus' were planned even in this older dell whitepaper [dell.com] suggests.

Re:Ok, So I've noticed a couple of corrections. (2, Insightful)

sedmonds (94908) | more than 11 years ago | (#5473225)

The pci and rambus busses don't need to keep up. The peak throughput only needs to be serviced within the scsi chain. Buffering on the scsi adapter could deliver a relatively high sustained transfer rate from the scsi chain to the pci bus, within pci limitations.

U320 SCSI (2, Informative)

Unix_Geek_65535 (625946) | more than 11 years ago | (#5473031)

Greetings fellow geeks :-)

U320/LVD SCSI is capabable of 320MB / sec not 320mbps.

3gbps ~= 300MB/sec. therefore it would not be be quite as fast as U320 SCSI.

Naturally 320MB/sec is the theoretical max bandwidth for the SCSI bus not the individual drives in the SCSI chain.

Live long and prosper

Re:U320 SCSI (0)

Anonymous Coward | more than 11 years ago | (#5473115)

Where the hell did you learn your math!? 3 gigabit/sec is 3000000000 bits/sec which is 375000000 bytes/sec which is 366211 kilobytes per second which is 357.628 megabytes/sec. Now before you start saying crap like "well that's before protocol overhead and blah blahh blah", so is the 320 megabytes per second speed of Ultra320. So serial attached scsi is actually 11.8 percent faster than ultra320 parallel scsi.

Re:U320 SCSI (1)

evilWurst (96042) | more than 11 years ago | (#5473141)

Five people modded this up without checking the math first...

3gbps = 3000mbps.

3000mbps / 8 = 375MB/s. There are 8 bits in a byte, not ten!

375MB/s (serial SCSI) is more than 320MB/s!

Re:U320 SCSI (0)

Anonymous Coward | more than 11 years ago | (#5473189)

Maybe you should have checked your math too. 3000 mbps / 8 != 375MB/s. You are forgetting that *bit uses 1000 as a divisor and *byte uses 1024. This means that 3000 mbps = 3000000 kbps = 3000000000 bps = 375000000 Bps = 366211 KBps = 357.628 MBps.

Re:U320 SCSI (0)

Anonymous Coward | more than 11 years ago | (#5473215)

Five people modded this up without checking the math first...
they didn't check the sig, either. Live Long and Prosper????

sheesh.

Re:U320 SCSI (1)

packeteer (566398) | more than 11 years ago | (#5473162)

Sorry but your math is off. Remember the whole 1024 bytes to a kbyte thing. 3 gigabits a second should come out to about 384 megabytes a second which is fast than U320's 320 megabytes a second but not by much. The added speed here is not a big issue as SCSI drives dont typically max out their available bandwidth for very long.

good performance.. but at what price? (5, Insightful)

thadeusPawlickiROX (656505) | more than 11 years ago | (#5473035)

Sure, this definately looks like it could be a great setup: fast, and compatable on multiple systems. But how much will this technology cost? Standard, run of the mill IDE hard drives are about a dollar per Gig. Regular SCSI is a few times higher, especially as drives grow in size. This will be a great advantage if the price range is in the middle of the range, but I doubt that. Now, this won't matter to those with plenty of money to burn on their servers, but would that added price be worth the new types of hard drives? I still don't even see a huge advantage to going Serial ATA right now, so this seemingly good idea could just be another good idea that won't pan out for most users.

Re:good performance.. but at what price? (0)

gunix (547717) | more than 11 years ago | (#5473080)

Well,most users are happy with a ATA/133 or perhaps a SATA150 disc. But there are those who require extremly fast data storage.

Just wait until they are gonna put a sniffer on a backbone.....

Re:good performance.. but at what price? (4, Insightful)

Magus311X (5823) | more than 11 years ago | (#5473150)

Not just fast, but reliable.

Not to say that ATA disks aren't reliable, but the components that are used in ATA disks are typically those that were outside the absurdly strict tolerances that are required for "enterprise-class" drives.

And yes, when it comes to speed, SCSI tends to rule the roost. Not only because you can throw 320MB/s down each individual channel, but you can toss enough devices on that channel to keep that overall speed sustained over longer periods of time.

Drives have very high burst speeds, but have it do lots of random data access constantly and watch speeds plummet. That's why a 10-disk striped array (with another 10-disks to mirror if you require redundancy, likely on another channel) tends to kick considerable ass. Because even if you're only sustaining say... 10MB/sec per disk, it's now 100MB/sec over the channel.

ATA storage is definitely cheap. If all that is required is just LOTS of storage, and performance and reliability isn't really critical, ATA is a pretty good choice. Of course then you could use robotic tape libraries as well.

SCSI also really ruled the server rooms because those expensive servers and storage systems simply didn't have ATA support. Period.

-----

Horray! (4, Interesting)

norton_I (64015) | more than 11 years ago | (#5473039)

Hopefully this will eventually lead to the elimination of the distinction between ATA and SCSI interfaces. Already the feature distinctions between the two are blurring, hopefully soon the interface will be the same and people will just decide whether they need fast or cheap drives. That would improve the quality of desktop class drives and lower the price on workstation/server drives, as well as make system managment a bit easier.

Re:Horray! (1, Interesting)

g4dget (579145) | more than 11 years ago | (#5473202)

Why would adopting a serial standard lead to "the elimination of the distinction"? When both were parallel, they were different.

The distinction is largely one of software and controller standards. SerialATA looks like an IDE controller, and SerialSCSI looks like a SCSI controller. The fact that both use a handful of wires in a thin cable to attach them doesn't change that.

Re:Horray! (0)

Anonymous Coward | more than 11 years ago | (#5473260)

did you read the second article in the posting? specifically this one:

http://www.computerworld.com/hardwaretopics/stor ag e/story/0,10801,78946,00.html

that's what he meant by elimination of the distinction.

Is this a trend? (5, Interesting)

Anonvmous Coward (589068) | more than 11 years ago | (#5473075)

I've only paid attention to HD controllers for the last couple of years or so. But I'm starting to wonder if we're seeing a pattern here. "We'll make everything more efficient by making it serial, and then years later when that's not enough we'll make it paralell to send even MORE data through!"

Anybody think we'll have a massive paralell trend in a few years?

Re:Is this a trend? (5, Informative)

TheShadow (76709) | more than 11 years ago | (#5473109)

I don't think so. The reason there is a tremendous push towards serial right now is because parallel interfaces create more interference at higher frequencies. The theory with serial is that you can push the frequency as high as you want without the interference.

CHEAP (0)

johnjones (14274) | more than 11 years ago | (#5473264)

wake up if its cheap then the drive people love it

its shake out time with people not buying and as such a way of reduceing costs is good...

what if

you only had to manufacture one drive controller and you could switch it between market segments
then if you want a high end SCSI drive you add a fast motor and bingo

thats the real reason

and its good because it means that SCSI will come down in price and people might get rid of SATA (its not going to happen but I can dream cant I )

regards

John Jones

I doubt it... (1)

Kjella (173770) | more than 11 years ago | (#5473157)

The very reasons interfaces are changing to serial is that it's very problematic to keep signals synchronized in parallell. So it's either "fast" serial, or "slow" parallell, and it looks like serial is winning. While fast parallell obviously would be the best, don't hold your breath for it.

Kjella

Re:I doubt it... (1)

lederhosen (612610) | more than 11 years ago | (#5473231)

If its not optical! Then every fiber transmits
data in parallel! But its no use at the moment
cause the electric2optical circuts is adding a
lot of latency so for short distance it is no
use, at least for now.

Re:I doubt it... (1)

Neon Spiral Injector (21234) | more than 11 years ago | (#5473256)

What I don't get is there already is a serial SCSI, it is called Fibre Channel. Right now it is clocked at 4 Gbits/sec. and there is no reason it can't go faster.

But I do agree about the problems with parallel. Thing about the interfaces called "parallel" and "serial", the old ports on the back of the computer. Sure the LPT ports were faster, but were very limited to the distance they could run because interference.

Also to get IDE over 33 Mbits/sec. they had to add an extra ground wire between each data wire to keep the noise down. SCSI always had extra wires, but they had to go to twisted pair (aka LVD) with in the cables to get any distance.

But FC is here today, it supports high, and huge cable lengths on optical cables, and respectible lengths on copper.

Re:I doubt it... (1)

Daniel Phillips (238627) | more than 11 years ago | (#5473265)

The very reasons interfaces are changing to serial is that it's very problematic to keep signals synchronized in parallell. So it's either "fast" serial, or "slow" parallell, and it looks like serial is winning. While fast parallell obviously would be the best, don't hold your breath for it.

Hypertransport is a good example of a serial/parallel interface. To get more bandwidth, you add more links in parallel, each of which is a serial link capable of carrying the whole traffic on its own, just slower.

It's too bad... (3, Insightful)

Quaoar (614366) | more than 11 years ago | (#5473076)

...that the speed limitation on data access is mostly the fault of the DRIVE, not the interface. Show me a drive that can achieve 3 gigabytes/sec and I'll be impressed.

Re:It's too bad... (2, Insightful)

Anonymous Coward | more than 11 years ago | (#5473194)

Informative? How about ignorant?

That bandwidth can be shared between many drives. The drive itself has cache, so it isn't always returning data from the platters. And it's gigabits, not gigabytes. Get a freakin clue.

Re:It's too bad... (1)

TheRaven64 (641858) | more than 11 years ago | (#5473217)

Show me a drive that can achieve 3 gigabytes/sec and I'll be impressed.

The interface runs at 3Gbps, not 3GBps. A standard SCSI interface can support at least 7 drives. This only 45MBps per drive on an U320 channel not counting protocol overhead. Quite a few SCSI drives can handle that speed.

Re:It's too bad... (0)

Anonymous Coward | more than 11 years ago | (#5473250)

Ultra 320 supports 16 devices on a bus (4 bit address) so with one id used for the controller (generally 7 or 15) this leaves 15 ID's for drives. I seem to remember that only the 8 bit SCSI standards limited the number of devices to 8.

Oh no, not yet another interface... (1)

hamster_nz (656572) | more than 11 years ago | (#5473079)

Argh! Who needs more standards! Why not just use fiber channel [pcguide.com]?

Re:Oh no, not yet another interface... (0)

Anonymous Coward | more than 11 years ago | (#5473107)

RTFA, it'll be fast than fibre channel.

Re:Oh no, not yet another interface... (0)

Anonymous Coward | more than 11 years ago | (#5473133)

Actually, 10 gigabit/sec (1.16 gigabytes per second) fibre channel products are on the horizon... That makes 3 gigabit look like a walk in the park.

Why... (0)

Anonymous Coward | more than 11 years ago | (#5473094)

have the difference then if its the same electrical and physical connector?

One format rules all. Agree on a friggin standard and be done with it. IT looks like its going that way.

why is serial better? (0)

Anonymous Coward | more than 11 years ago | (#5473096)

This is probably not the place to ask this, but with all these geeks in one place, why not. Why is serial faster/better? It stands to reason in my head anyways, that parallel would allow more throughput. What am I missing?

Re:why is serial better? (2, Informative)

ChaosMagic (657047) | more than 11 years ago | (#5473135)

I don't know the technical details but I would imagine that in a virtual world where everything worked in theory, you'd be right, parallel would be faster. It stands to reason that however fast you can get a serial link, you can just put it together with a few more and have a parallel one just as fast.

I think the problem(s) come when you have to take into account keeping parallel lines in synch with one another, accouting for lost bits, and breaking down/putting back together all the information at either end. This all adds up in overhead for a parallel connection, where a serial connection just lets the information go through the line with little or no pre/post processing or synching to worry about.

Parallel Interface? (1)

Kenshin (43036) | more than 11 years ago | (#5473104)

SCSI is very close to joining ATA in leaving a parallel interface design behind in favor of serial one.

If I'm not mistaken, doesn't SCSI stand for "small computer serial interface"?

Re:Parallel Interface? (-1, Redundant)

Anonymous Coward | more than 11 years ago | (#5473119)

No.

Re:Parallel Interface? (0, Redundant)

catmaker (209612) | more than 11 years ago | (#5473124)

If I'm not mistaken, doesn't SCSI stand for "small computer serial interface"?

You're mistaken. It's Small Computer System Interface.

Re:Parallel Interface? (4, Informative)

aussersterne (212916) | more than 11 years ago | (#5473132)

SCSI: Small Computer Systems Interface

descended from

SASI: Shugart & Associates Systems Interface

Benefits of SCSI? (1)

DarthWiggle (537589) | more than 11 years ago | (#5473159)

Ok, this is not a fanboy post on either side. But I'm wondering what the benefits of SCSI are in this day and age. Is it just the ability to have more than four drives? If that's it, are IDE/SATA drives somehow hard-limited to just four connections, or is that a motherboard limitation that hardware vendors stubbornly refuse to leave behind?

I keep hearing that SCSI drives are better for hardcore media editing and for servers, but I'm curious why. Is there a compelling advantage for desktop users (or even servers)?

I have to admit, I've got a box with two IDE drives and two CD/DVD drives, and I'm irritated that I can't keep my IDE ZIP drive installed or add another drive (transferring data is a pain in the butt...). It would be awfully nice just to throw another drive in the chassis, and add the free space to my existing partitions.

I dunno, I'll be in the market for a new desktop in the next year or so, so I'm trying to figure out now what the best hardware arrangement is.

Pizzle.

Re:Benefits of SCSI? (2, Interesting)

ProfMoriarty (518631) | more than 11 years ago | (#5473228)

Uhmmm ... you CAN have more than 4 IDE devices ... what you need is more IDE channels.

Each IDE channel can have only 2 devices, a master and a slave.

The more IDE channels you have, the more devices you can have. Currently, on my Motherboard, it has 4 channels, (2 for "standard" IDE connections, for 4 devices, and 2 for "RAID" IDE connections, for another 4 devices).

In fact, there are a couple of MOBO mfgs that have 6 channels (2 + 4 RAID channels, for maximum throughput you would have only 1 device per RAID channel.) ... however, you don't need to configure the RAID array, and could have 12 IDE devices.

Currently, I have:

  • 60G - master - channel 1
  • 60G - slave - channel 1
  • CDRW - master - channel 2
  • DVD - slave - channel 2
  • 40G - master - channel 3

BTW, it's really nice not to partition anything, and have a whole drive dedicated to an OS.

Re:Benefits of SCSI? (2, Informative)

khuber (5664) | more than 11 years ago | (#5473246)

Better drives that are designed to run 24/7 with load. The drives usually have lower seek times/lower rotational latency. Some of this comes at the cost of heat and noise which Joe Consumer might not tolerate. Seek times are incredibly underrated, btw. The SCSI interface itself really doesn't have much advantage over ATA, but the industry builds its best drives for SCSI/FCAL.

Re:Benefits of SCSI? (2, Informative)

MoralHazard (447833) | more than 11 years ago | (#5473266)

There is no "hard-limited" maximum of 4 IDE drives per motherboard. Most boards have two IDE channels built in, and IDE will only support 2 devices per channel, so you get four devices from the board. However, you can buy many, many boards that have more than that, especially lately (Abit's AT7/IT7 models come to mind).

Most board manufacturers include only two IDE channels because that's how many are generally built into north-bridge chipsets. The Abit boards mentioned above use an additional Promise HPT374 chip to provide FOUR extra IDE channels, for a total of TWELVE IDE devices, altogether.

If you want more IDE devices than your board supports natively, you can just buy PCI cards that have more IDE channels. Promise, SIIG, and Highpoint all make really cheap cards that have an extra two channels, or four more devices.

SCSI limitations are similar. You only get 15 devices PER BUS, but you can add as many devices into your system as you have PCI slots and IRQs for. You can buy an Adaptec 29160 card (dual busses) and plug 30 hard drives into it. Buy four of them, and can have more than 100 drives.

Firewire? (2, Interesting)

TheRaven64 (641858) | more than 11 years ago | (#5473174)

SCSI is expensive, FireWire is proven technology. Wouldn't it be more sensible to use FireWire? [sucs.org]

Re:Firewire? (5, Informative)

torre (620087) | more than 11 years ago | (#5473212)

SCSI is expensive, FireWire is proven technology. Wouldn't it be more sensible to use FireWire? [sucs.org]

Firewire is low end consumer product...even with its successor (which is taking longer than expected to ship) running at 800Mbits/s (100 Megabytes/second) it falls short of current SCSI technology running @ 320MB/s. As such there is no one who would seriously consider firewire for a large scale server handling many gigabytes/terabytes of data. Firewire is just too slow of a bus for big needs, but does fills its convenience needs in the consumer market. Everything has it's own niche... that's why heavily marked up servers/mainframes/supercomputers still exist instead of cheaper home machines which just can't fill the requirements.

Re:Firewire? (1)

khuber (5664) | more than 11 years ago | (#5473213)

Firewire (IEEE 1394a/b) really isn't the right technology for disk data transfer. It's an extremely sophisticated interface that has features for synchronizing realtime multimedia stuff. It's also expensive.

-Kevin

Re:Firewire is not fast enough (1)

benzapp (464105) | more than 11 years ago | (#5473243)

SCSI is expensive, FireWire is proven technology. Wouldn't it be more sensible to use FireWire? [sucs.org]

I quote from the article you posted: The current generation supports transfer speeds of 800Mb/s (100MB/s, the same as most ATA controllers).

This discussion is about Serial SCSI which will have a peak throughput of 384MB/s. Clearly, firewire is insufficient.

Re:Firewire? (1)

iotaborg (167569) | more than 11 years ago | (#5473249)

I suppose the main issue is that no one makes true firewire hard drives (afaik), so a firewire bridge would reduce performance. Though adding more firewire channels does seem a lot cheaper than fewer scsi channels.

no longer pronounced "Scuzzy." (3, Funny)

jfisherwa (323744) | more than 11 years ago | (#5473183)

If SCSI is pronounced "scuzzy."

And the full acronym for "Serial attached SCSI" is SASCSI..

How exactly would we pronounce that? Sacksie? Sasky? Oh God, I bet it will be a silent C. .. "Sassy."

Yay, my computer iss really sspeedy now that I've upgraded to the new SSSASSSSSY DRIVE !@#!@^#^$^$#! [colonpee.com]

Jason Fisher. :P [colonpee.com]

Does SCSI now compete with firewire2 ? (1)

ozzee (612196) | more than 11 years ago | (#5473209)

Firewire2 or IEEE1394B is already shipping and purports 3.2Gb/sec.

And how about 10Gbit Ethernet ? What's stopping you from using this as a drive interface ?

It's coming to a point where the difference in connection standards is so unimportant that you can see that in the not so distant future you'll be wiring up every peripheral (including your monitor and keyboard) with the same type of cable and the old Sun adage - "The network is the computer" becomes literal.

Fanboy? (2, Funny)

AtariDatacenter (31657) | more than 11 years ago | (#5473240)

> But before this thread turns into a SCSI
> fanboy vs. ATA fanboy flame war...

FWIW, the alternative name for fanboy is "fanboi". An even more disrespectful version of the term. (As if fanboy wasn't disrespectful enough for some people.)

It's already here... (0)

evilviper (135110) | more than 11 years ago | (#5473241)

Serial attached SCSI, as the standard will be known, is expected to be ratified sometime in the second quarter of this year

Gee, serial SCSI will be here soon you say? So what does that make Firewire and Fibre Channel?

It seems to me that the different branches of serial SCSI should try to unify, and they could work together, rather than in competition (eg. "Should I get an external SASCSI drive, or a Firewire drive?").
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