Scuzzy wuzzy wuz a bear…
no, but seriously folks,
What is a scuzzy?
Something about a port for your computer like a super fast usb…
how fast? how expensive?
why isn’t it more pooopoooolar?
“Mmmmm, Sacrilicious…” – Homer Simpson
If you need a graphic solution, http:\ alk.to\Piglet
Actually, it’s SCSI, another one of those wonderful acronyms that means you don’t have to remember what it actually means (Small Computer System Interface? I don’t remember anymore).
On a small scale, SCSI is used a lot for an interface between your computer processor and a fixed disk. SCSI has some advantages over the IDE/EIDE interface in that you can have seven devices on one host, instead of just two. It’s very handy for computers like file servers that need many disk drives, especially RAID arrays (Redundant Array of Inexpensive Disks - so callims somethng a RAID array is redundant? I digress). RAID is a way to link several disks together (between two and six similar drives) so that if one drive dies, the other drives can survive with no loss of data.
SCSI also applies to other peripheral devices like tape drives, CDRom drives, DVD, and so forth. A SCSI interface can also be used between, say, a laptop computer and a docking station/port replicator, so you can plug your laptop into your network/keyboard/mouse/monitor while at work.
SCSI is becoming more popular. It has been around for a while and has gone through several revisions (SCSI/SCSI II/USCSI). Why SCSI devices are more expensive is one of the great questions that many support folks ask. A 10G EIDE hard drive can be had for $125, but the SCSI version runs sometimes double that amount. It isn’t like the logic or chipset is horrendously complex or proprietary.
This sig not Y2K compliant. Happy 1900.
The big deal with SCSI is throughput. From the SCSI Trade Association website:
The daisy chain (up to seven peripherals) is a nice feature, but data throughput is what allows SCSI devices to command the prices they do. Most of the time it’s not worth it, but I’ll be buying SCSI hard drives for my next work machine.
I don’t think there is much performance difference between IDE and SCSI with current standards. In fact, a $300 IDE drive is likely to be faster than a $300 SCSI drive. However, the fastest SCSI drives out there are faster than the fastest IDE drives.
SCSI does have one big advantage - besides allowing 7 devices per channel, it allows a longer cable, about 5 feet I think. This means you can use it for external disk drives, scanners, printers and other peripherals which need more bandwidth than parallel or serial ports. IDE is only good for internal drives. SCSI is also supposed to be better suited for multitasking - i.e. handles concurrent accesses better.
However, SCSI is getting a bit old. You have to set a unique ID on each device, usually manually. And you can’t do a hot plug - i.e. you have to turn off the power before adding or removing a device. USB and IEEE-1394 (‘FireWire’) interfaces both address these problems, and are starting to replace SCSI - USB for low bandwidth peripherals and IEEE-1394 for high bandwidth. Apple traditionally used SCSI, but the newer PowerMacs only have USB and IEEE-1394.
SCSI drives are more expensive than IDE drives for two reasons: 1) They sometimes have other performance improvements than just the interface, and 2) They are targeted at high end users, who are willing to pay more.
To reiterate, while I don’t believe the additional cost is justified most of the time, SCSI still leads in data throughput.
Because the S-ystem C-an’t S-ee I-t.
No, seriously, they have been occasionally hard to configure. Either they (SCSI devices) used to work perfectly right away or else you were plagued with issues.
We Mac users had them as standard equipment since the Mac Plus back in…uh…1985? We used to say “it’s called ‘scuzzy’ for a reason” and would curse at the voodoo necessary to get balky devices to work on the chain – sometimes a drive or scanner would only work on one position on the chain, even though it isn’t supposed to notice or care; some devices didn’t ‘like’ certain SCSI ID numbers; some cables worked better between device 3 and 4 than between devices 4 and 5; some chains would work better unterminated, although you’re supposed to need to have them terminated at both ends; and so forth. And don’t even get me started on the weirdnesses of jumper pins for internal SCSI hard drives!
Nevertheless, I’ve often run computers with the whole chain occupied. I had my old 7100 running for quite some time with two internal hard drives, a CDROM drive, a SyQuest, a scanner, a Jaz drive, and a Zip drive. Most of the time I just ran SCSI probe to see what addresses were still available, set the new device to that address, hooked it onto the daisy chain, and restarted; most of the time no software drivers were necessary, I just turned the computer back on and there it was. And with the single exception of a really ANCIENT DaynaFile (for reading 5 1/4" PC diskettes on the Mac; remember those?), they were all bootable. Well, OK, not the scanner 
Macs don’t come with SCSI built in anymore. New Macs use FireWire for the faster, hi-performance devices, and USB for slower peripherals; both are hot-pluggable, neither give you address-conflict headaches, and neither have those huge ugly umbilical cords with the freight-train sized connectors.
Just the same, I’m glad I picked up my PowerBook before they phased SCSI out. It can be a nice thing to have.
Disable Similes in this Post
beatle,
If you are talking hard drives, yes, a SCSI hard drive is about 80 MB per second of transfer rate but the average Joe can’t afford that in their home systems. The nice thing is, average Joe can get the IDE Ultra ATA at 66 MB transfer rate per second at about 2/3rds the cost…I think you would agree with me there.
SCSI is a great technology for servers but for most users, a SCSI drive or SCSI interface is not needed.
Me, although I can afford a SCSI hard drive in my new system, I am going for the IDE Ultra ATA at 7200 rpm… I can then afford some nifty graphics and web programs to further my business
BTW Rory,
If you ever need to get real technical information, check out www.whatis.com
This is a great resource that I use quite often to help me explain things to average non-computer people. I new the stats on the SCSI hard drives, but had to ensure I was giving you correct info…anyhow, that’s a good resource.
Faster, at the limit, than EIDE by a good margin. As for how expensive, that depends on the size of drive. For smaller (4-9 Gb) drives, there is usually only a few ($10-$20) dollars difference, but for bigger drives, they can be much more expensive - usually about twice for an 18 Gb drive, and 3 times for a 40 Gb drive. Then you can also get RAID arrays and so forth if you need more than about 50 Gb.
Who says it isn’t popular? It’s very popular. SCSI was the standard HD interface on DECs, Suns, HP S3/700s, IBM workstations, Macs, Amigas, and tons of other systems for many years. In fact for a while, the PC was probably one of the few systems to <i>not</i> come standard with SCSI. But at the time, it didn’t matter much, because PCs couldn’t (back then) really use big or fast drives (which tended to be SCSI, not IDE) due to other limitations, such as having about the worst filesystem of any operating system on the market.
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peas on earth
It should be noted that the SCSI interface isn’t just designed for disk drives. My scanner uses a SCSI interface, and I’ve seen the SCSI interface specs for printers (but, I’ll confess, I’ve never actually seen a SCSI-based printer).
Back when the 486 was a really fast computer I was convinced that the SCSI interface was going to take over the world. The SCSI interface didn’t have the (then) 512MB IDE size limit or the (then) two-drive IDE limit, SCSI disks were both faster and larger, you could hang other devices on your SCSI cable, … But then the IDE folks fixed their limitations, IDE drives remained significantly cheaper than SCSI drives (the SCSI interface requires significantly more electronics on the actual drive than the IDE interface does), and SCSI never really took off in the PC world. Ah, well, wrong again…
The Fuji Pictrography photo printer uses SCSI. Not exactly a common printer, but it’s pretty much the standard for professional photo printing, I believe. We have one at work connected to a Sun workstation.
My father has a laser printer with a SCSI interface, but not for connecting to the PC - it’s for connecting an external 40MB hard drive where the fonts are stored!
As a Mac dude for years and years, I gotta say, I dig SCSI. No master-slave strangeness, room for lots of drives, and where you put a device on the chain usually doesn’t matter. Some SCSI setups, I will admit, are almost voodoo-like in their strangeness, but I know most of the tricks, so I don’t mind. At home, I have a SCSI ZIP drive and a SCSI CDRW drive, both external.
I recall a printer in Apple history that used SCSI as its printing interface (lots of Apple printers had SCSI ports so that you could connect the printer to a hard drive and let it download its fonts from there rather than the printing computer), but I’m too lazy to look it up right now…think it was the LaserWriter II SC or something like that…
I’d like to close by stating that it’d be a lot more fun to pronounce “SCSI” as “sexy” rather than “scuzzy”.