CompuServe Messages

#Hard Disk Drive

    16-Dec-86 10:14:56
Sb: #43992-#Hard Disk Drive
Fm: Tom Cattrall 72767,622
To: Ben Blish 72667,1341
Ben– Most all drives on micros are ST506 drives. SCSI is the interface between the computer and the controller, while ST506 is the I/F between the controller and the drive. Perhaps a picture would make it more clear for you and any others… ———————– | Computer I/F bus | ———————– V <—— This is the Amiga bus ——————- | SCSI interface |—> to other controllers for disk, tape, etc. ——————– V <—— This is the SCSI bus ———————– | disk controller #1 |—————– <–These are 2 ST506 connections ———————– | V V ———————- ———————- | Hard disk drive #1 | | Hard disk drive #2 | ———————- ———————- C Ltd sells the SCSI I/F. You can buy the disk controllers made by Adaptec, Western Digital, OMTI and others for <$200. The SCSI interface will support several controllers which may be for disk or tape. Most disk controllers only support 2 drives but with 5.25 disks now in the >200Meg range you probably don't need more than one controller. The controllers typically are the same size as a 5.25" drive and bolt onto the top of the drive. My preference in disk controllers is the Adaptec ACB-4070 which supports 2,7 Run Length Limited (RLL) encoding. This allows 50% more data on a disk than a simple controller. ie, 30meg from a 20, or 120 from a 80. I think other outfits now have RLL controllers but this is the one I'm familiar with. If you contact a mail order outfit for a controller make sure you ask for SCSI as IBM PC (ugh) versions exist for most of these and they are far more common. Tom