HELLER@cs.umass.EDU ("From the screen of Deneva... 24-Jun-1988 0809") (06/24/88)
I have built my own hard drive sub-system for my 1040ST (the 520ST would be the same). This is what I did: 1) I purchased Supra's DMA to SCSI adapter from the store where I purchased my ST (cost $125.00). Contact your local Atari dealer or Supra directly for info on how to get this. There are several other companies that sell DMA to SCSI adapters for the ST. 2) I purchased via mail order an Adaptec 4000 SCSI to ST506 disk controller from The Computer Surplus Store (715 Sycamore Drive, Milpitas, CA 95035, 408-434-0168 (phone orders: 408-434-1060)). This cost me $89.00. These people also sell the Adaptex 4070 controller. The 4000 is a straight dual drive ST506 controller, the 4070 is a RLL controller (also 2 drives I believe). 3) I purchased from JameCo an IBM-PC/XT clone box & power supply (JameCo sells all of the pieces to build-your-own IBM-PC XT or AT clone - the boxes, power supplies, mother boards, etc.) The case went for about $30.00 and the power supply for about $100.00. The box is rather large and the power supply rather beefy - I plan to add a 1/4" cartidge tape drive (I already have a SCSI to QIC-36 tape drive controller). You might do with a smaller box and smaller power supply. Probably any full-height or dual 1/2 height drive box will do (use a single 1/2 height drive and put the interface board where the second 1/2 height drive would go). Priority One sells disk drive boxes, as to various other mail order companies. Check out the back of BYTE magazine and/or The Computer Shopper. 4) Ordered (from various electronics suppliers) ribbon cable (50 conductor) and connectors: 50-pin header connectors (SCSI bus), 34-pin edge connectors (hard disk interface cable), a 20-pin edge and header connecters (hard disk interface cable), and a 2-pin power connector set for the Surpa board. 5) I purchased an ST251 (40+ meg, half height hard disk) from Bull Dog computer. I think I paid about $400 for this drive. It even came with MS-DOS software for formatting and partitioning the drive (not much use to me!). It all works. The Supra board came with Supra's hard disk utilities disk - had no trouble formatting and partitioning the drive. I have it setup with two partitions: a small (2MEG) GEM partition and a large (38+Meg) OS-9 partition (I mostly run OS-9 rather than GEM). The Supra DMA adapter came with info on adding your own hard disk controllers and the Utilities disk had an ARC file with picture files showing the board layouts of the Supra board and seveal popular SCSI/ST506 controller boards. It is not really hard. So long as you keep track of pin one on the various connectors, you should not have trouble. Oh, one trick: 1/2 the pins on each of the ribbon cables are grounds - you will notice that the contacts on the PC boards will have all (or most) of the pins or edge fingers wired together - this can be used to verify the that the connectors are correctly oriented. Also: on the power connector set for the Supra board - it is a good idea to wire the female end to the "live" (power supply) end. This prevents fireworks should the power be applied and the connector is just hanging loose - prevents shorting out the power supply to ground. Robert Heller ARPANet: Heller@CS.UMass.EDU BITNET: Heller@UMass.BITNET BIX: Heller GEnie: RHeller FidoNet: 322/410 (Locks Hill BBS, Wendell, MA) CompuServe 71450,3432 Local PV VAXen: COINS::HELLER UCC Cyber/DG: Heller@CS