kevin@arnor.UUCP (Kevin Goroway) (07/17/89)
Do these exist anywhere for the amiga? -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= - Worcester Polytechnic Institute|"It happens sometimes, people just explode, - = Worcester, MA (IBM for summer) | natural causes." -Repo Man = -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
lphillips@lpami.wimsey.bc.ca (Larry Phillips) (07/18/89)
In <12227@grebyn.com>, ckp@grebyn.com (Checkpoint Technologies) writes: >I think the Summary line says it all. SCSI gives superior performance, >with the right controller and the right drive. ESDI is cheaper, but that >won't be true for much longer. Sigh. Here we go again. A blue shirt is larger than a red shirt. Huh? Doesn't make much sense, right? Well, neither does saying that SCSI gives superior performance, especially if you are comparing it to ESDI. Many SCSI drives (the 'embedded SCSI' type), _ARE_ ESDI drives, while others are ST506 (MFM or RLL), while yet others are proprietary interfaces _Between the Built-In Controller and the Drive_. In addition, an ESDI or ST506 drives may be easily driven by a SCSI host adapter simply by supplying the appropriate controller. ESDI is a controller to drive interface, and SCSI is a host adapter to controller interface, ie. SCSI is _NOT_ a controller to drive interface. The speed you obtain will depend entirely on the maximum speed of the slowest link in the chain, whether it's the OS, the host adapter, the controller, or the drive, and this is true no matter where the controller physically resides. >First comes the logo: C H E C K P O I N T T E C H N O L O G I E S / / > \\ / / >Then, the disclaimer: All expressed opinions are, indeed, factual. \ / o Indeed? >Now for the witty part: I'm pink, therefore, I'm spam! \/ -larry -- Real Amiga hackers write printer drivers using Metascope. +----------------------------------------------------------------------+ | // Larry Phillips | | \X/ lphillips@lpami.wimsey.bc.ca or uunet!van-bc!lpami!lphillips | | COMPUSERVE: 76703,4322 | +----------------------------------------------------------------------+
ckp@grebyn.com (Checkpoint Technologies) (07/18/89)
I think the Summary line says it all. SCSI gives superior performance,
with the right controller and the right drive. ESDI is cheaper, but that
won't be true for much longer.
--
First comes the logo: C H E C K P O I N T T E C H N O L O G I E S / /
\\ / /
Then, the disclaimer: All expressed opinions are, indeed, factual. \ / o
Now for the witty part: I'm pink, therefore, I'm spam! \/ggibeau@ucqais.uc.edu (George Gibeau) (07/19/89)
In article <314@arnor.UUCP>, kevin@arnor.UUCP (Kevin Goroway) writes: > Do these exist anywhere for the amiga? > It's not so much as do these exist for the Amiga, but can the Amiga be made to take advantage of them. I run an OMTI ESDI controller in my AT (it does both ESDI and RLL), so if you can come up with a st-506 16bit interface with appropriate device drivers for the Amiga, then I am sure the OMTI will work just fine. :-) George -- Definition of HELL - A room full of MACS with all the right software ............on 5.25" disks ;-) UUCP: ucqais.uc.edu!ggibeau BBS: (513) 721-7977 GT NODE: 006/005 US Snail-Dept of Biology ML 06, University of Cincinnati, Ohio 45221
lphillips@lpami.wimsey.bc.ca (Larry Phillips) (07/20/89)
In <12230@grebyn.com>, ckp@grebyn.com (Checkpoint Technologies) writes: > No argument, that's exactly correct. ESDI and SCSI are not > necessarily exclusive. If you're using a SCSI interface to an EDSI > controller and drive, you'll get ESDI performance. If however you're > using one of the newer embedded-SCSI drives, you can get better > performance than that. If your ESDI controller were in a Zorro plug-in > card (if one were available), then that possibility is not present. True, but only if the embedded controller talks to the drive in something faster than ESDI. The point is not to say that SCSI is not fast, but to say that it is not the SCSI interface that sets the upper limit in most cases. You can also get controllers that do a lot of buffering, increasing the burst throughput, and they can be had both 'native' and SCSI. > The Amiga bus is limited to about 3.6 Megabytes per second > bandwidth. ESDI's transfer rate is 15 megabits, which is about 1.88 > megabytes per second. I've heard of 24 megabit per second (3 megabyte > per second) SCSI. SCSI maxes out at 1.25 MBytes/second. SCSI-2 maxes out at 4.5 MBytes/second. The latter utilizes a different set of protocols, generally known as synchronous SCSI. If you have a drive that can talk sync, and a host adapter/driver that understands it, you will indeed be able to use faster drives. > That sounds to me like SCSI provides the capability > for higher performance. Not at all. The drive and controller provide the capability for higher performance. SCSI allows a more general interface to a wider variety of peripherals. By its very nature, SCSI has no speed value. It will talk on a bus at the speed of whatever it is talking to at the time, whether it be a hard drive, a streaming tape, a host adapter, or a paper tape punch. -larry -- Real Amiga hackers write printer drivers using Metascope. +----------------------------------------------------------------------+ | // Larry Phillips | | \X/ lphillips@lpami.wimsey.bc.ca or uunet!van-bc!lpami!lphillips | | COMPUSERVE: 76703,4322 | +----------------------------------------------------------------------+
ckp@grebyn.com (Checkpoint Technologies) (07/20/89)
In article <640@lpami.wimsey.bc.ca> lphillips@lpami.wimsey.bc.ca (Larry Phillips) writes: > >controller interface, ie. SCSI is _NOT_ a controller to drive interface. The >speed you obtain will depend entirely on the maximum speed of the slowest link >in the chain, whether it's the OS, the host adapter, the controller, or the >drive, and this is true no matter where the controller physically resides. > No argument, that's exactly correct. ESDI and SCSI are not necessarily exclusive. If you're using a SCSI interface to an EDSI controller and drive, you'll get ESDI performance. If however you're using one of the newer embedded-SCSI drives, you can get better performance than that. If your ESDI controller were in a Zorro plug-in card (if one were available), then that possibility is not present. The Amiga bus is limited to about 3.6 Megabytes per second bandwidth. ESDI's transfer rate is 15 megabits, which is about 1.88 megabytes per second. I've heard of 24 megabit per second (3 megabyte per second) SCSI. That sounds to me like SCSI provides the capability for higher performance. -- First comes the logo: C H E C K P O I N T T E C H N O L O G I E S / / \\ / / Then, the disclaimer: All expressed opinions are, indeed, factual. \ / o Now for the witty part: I'm pink, therefore, I'm spam! \/