rb@cci632.UUCP (Rex Ballard) (07/26/86)
This, among others, was found in net.micro.mac, however, I thought it might be of interest to ST users as well, I would simply suggest looking through net.micro.mac to see more options on an SCSI drive. In article <106@van-bc.UUCP> sl@van-bc.UUCP (Stuart Lynne @ SLI) writes: >In article <541@hope.UUCP> deano@hope.UUCP writes: >> The Challenge of the week.... >>. >> I understand that it is fairly simple to hook up a Hard Disk to >>the MAC+ SCSI Port. The Way I understand it is... With the ST, you will need to get an SCSI adapter, I currently know about the Supra card, let's hope others follow, especially Atari. (Neil, any chance of a $100 SCSI interface?). >>1. Get an off the shelf hard drive at your local electronics surplus. >>2. Hook a SCSI Disk controller to the drive. >>3. Hook the controller to the MAC+ SCSI port (custom cable?) >>4. Tell the Mac that there is a H.D. (modify H.D. 20 DOC.?) >>5. format dialog should magically appear, and your on your way. >>. > >It's even easier. > >To assemble the hardware. > > 1. Buy an off the shelf case & PS for about $50 > 2. Buy a Seagate ST225N (specify rev 9 firmware) for about $450 > 3. Make a small cable with 50 pin header and 50 pin amphenol connectors > 4. Bolt together case, PS and drive. > 5. Connect to Mac+ with Apple System Cable and adapter cable. > >Total cost should be around $550. I got all my stuff in Canada so I can't >be sure about US prices. Hamilton Avnet has a good supply of these drives >with nationwide offices. You may be able to get a better price if you live >in an area where you can shop around. > >Specifically the Seagate has a problem with "Unit Attention". When the Mac >is reset the SCSI bus is reset. The Seagate goes into a Unit Attention state. >The Mac+ ROM does not know how to cope and cannot boot off the drive. Turning >the drive on and off (several times) will eventually allow Mac to boot from >the drive. With newer drives (rev 9 firmware does work) use the Mode Select >command to set turn the Unit Attention "feature" off. This needs to be done >only once (at the same time you format the drive is appropriate). Be sure >to specify that you need at least rev 9 firmware. There are a bunch of the >older drives in the field. If you do get one ask to have it sent back to the >factory to get new firmware. Does anybody know, does the Supra board have this problem? >The Seagate is fairly fast (around 40ms average seek). Any faster would be >wasted on the Mac. The main limitation is data transfer. Using the best >case, a fast blind transfer will still only allow you to format with a >2:1 interleave (not Apples routines, they will only get you 3:1). The Atari doesn't have this limitation (has real DMA port), does it? >The Seagate is a half height drive and not unduly noisy. I've run two of them >on my desk without a case without being to annoyed at the noise. In a case >under the desk, and you'll forget it's on. >All in all the drive seems to be fairly reliable, fast, and very inexpensive. >(The only data loss I've encountered was due to user incompatence, and >I'm the only user!) > >There are other SCSI compatible drives about to come onto the market. Priam >with a 60MB, Quantum 80MB, Maxtor 240MB, CDC 240MB, etc. For the most part >embedded SCSI will simplify your life when you write the driver (for example >no need to tell the controller about the disk geometry, its in it's firmware >so just say format and away you go). Also embedded SCSI is allowing the >manufacturers to lower their prices by improving their production yields. >(Because they handle the format, they can use advanced slip sector techniques >to eliminate bad sectors, allowing them to use what would have been a bad >platter if it had been put into a 506 style drive.) It also allows them to >use RLL encoding or other techniques to increase the storage without adding >extra heads/platters. Priam uses this technique to make a 60MB SCSI out of >a 40MB ST506 drive. This "absolute purity required" has resulted in a number of "surplus" ST-506 drives available as "used" that could still work effectively with a good SCSI controller. It may be possible to get a $100 controller, and a $100 drive, and have a hard disk for as little as $400, including Supra card. >So we should see an avalanche of large, cheap SCSI drives in the final >quarter 1986. Especially considering there is also an SCSI card for the "PC" now. If Atari either upgrades their DMA port, or comes out with their own SCSI adapter, the drive options would be unlimited. >Stuart Lynne ihpn4!alberta!ubc-vision!van-bc!sl > >Disclaimer >========== >I am not in any way associated with either Seagate Technologies >Hamilton Avnet, other than having purchased several drives from them. >I am not associated with any of the other disk drive manufactures mentioned >in this article and have not used their products. I haven't heard from Atari on this one, at least the Supra card is available. Kinda makes an "integrated drive" from Atari look dissappointing doesn't it?