What is Scuzzy? (SCSI)

[Lodan_SD]

I guess I still don't fully understand SCSI, I've looked on Wikipedia, and I've compared it to SATA and other formats, and I still don't fully get it. I guess from what I've read it's in some ways better than SATA, but is also more costly, thus less used. But what exactly makes it better?

[Electronics Wizardy]

scsi is dead and old. No one uses it. 

 

SAS is the serial version and support more features than sata like multiplers, 12gb/s, full duplex, and longer cables.

[ZcanKal]

Even my SAS 2.0 card has the same transfer speed as SATA and with another cable can support up to 8 drives.

[Radium_Angel]

15 minutes ago, Lodan_SD said:

I guess I still don't fully understand SCSI, I've looked on Wikipedia, and I've compared it to SATA and other formats, and I still don't fully get it. I guess from what I've read it's in some ways better than SATA, but is also more costly, thus less used. But what exactly makes it better?

SCSI was the (almost) original interface for hard drives,. MFM and RLL were actually first, but SCSI was the standard, adopted from the server world.

It allowed drives to read and write at the same time, something you couldn't do with IDE drives, and until the advent of SSD storage, was the king of the throughput world. SAS, Serial Attached SCSI is the logical successor, but cost is a factor there.

 

While SCSI has been surpassed in the home market, the Adaptec 39320U cards were great fun to play with (your could daisy chain 8 drives per channel without loss of R/W speeds) and can be had for pennies, but the old SCSI drives are quite worn out (as evidenced by their noise) so I wouldn't put any critical data on one. 

 

They are not worth buying for anything serious now, but great in a retro box and beat the snot out of IDE and SATA gen 1 drives.

[mariushm]

6 minutes ago, Radium_Angel said:

They are not worth buying for anything serious now, but great in a retro box and beat the snot out of IDE and SATA gen 1 drives.

Not even then... you can buy now SATA to IDE adapters.. if you find a hdd that can still work in SATA 1 mode  (1.5 gbps) or if you're lucky even a SSD, then you're good to go.

 

jMicron makes a bridge controller chip which is used a lot by Chinese companies to make such adapters, they're less than 5$ a piece, here's an example: http://www.dx.com/p/jm20330-2-5-3-5-sata-to-40-pin-ide-adapter-card-green-black-241466#.Wteu_H9RVhE

 

[Radium_Angel]

1 hour ago, mariushm said:

Not even then... you can buy now SATA to IDE adapters.. if you find a hdd that can still work in SATA 1 mode  (1.5 gbps) or if you're lucky even a SSD, then you're good to go.

 

jMicron makes a bridge controller chip which is used a lot by Chinese companies to make such adapters, they're less than 5$ a piece, here's an example: http://www.dx.com/p/jm20330-2-5-3-5-sata-to-40-pin-ide-adapter-card-green-black-241466#.Wteu_H9RVhE

 

But IDE is your limiting factor. And SCSI's capability to read and write at the same time will win hands down.

[mariushm]

Well, you can send reads and writes through cable which is useful if you have multiple devices on a cable but being able to read and write at same time on single hdd isn't such a big thing. You'd read and write data in 2 different locations so between the read and write you'd still have heads moving which means latency.

 

With a SSD on a sata->ide adapter you'dd have <1ms access time to any read/write ..doubt any scsi drive could do this.

[Mark77]

I still use a PCI-E SCSI setup for my scanners (slide scanner and flatbed optical scanner).  But other than that, the other posters are right, the interface is basically dead.  It was a bus topology, so very sensitive to things such as termination and even malfunctioning of an individual device or the cabling itself.  SAS has fully superceded it.