cmv@ihuxz.ATT.COM (Craig Votava) (02/19/88)
Here is the head select upgrade repost for the unix-pc. I have talked with Convergent about the status of the PAL equations, and they said that they didn't care what happens to them unofficially; officially, they will not go to any hasstle to release the information. I take that to mean that I can't post them to the net (which I won't), but they should be obtainable if you're persistant enough. /* Written 12:23 pm Nov 9, 1987 by looney!cmv in looney:unix-pc.general */ /* ---------- "9 Head Hard Disk Working on 7300!" ---------- */ I can't believe it, it actually works!! In fact, it worked the first time no less, with no problems, I really couldn't believe it! I actually have all 9 heads working on the hard disk drive of my unix-pc!!! Here's the scoop: After MONTHS of snooping around I got some very nice help from both Convergent folks and a VAR in NJ called Computer Integration Associates, and eventually aquired the upgrade kit to make my 7300/3b1 address more than 8 hard disk heads. I am currently talking with Convergent Technologies to find out the proprietary status of the information they gave me, to see what we can do about getting the stuff out to the general public. The following description is a general overview that does not violate any proprietary status. The actual name of the kit is "FIELD SERVICE P5.1 UPGRADE REWORK INSTRUCTIONS" and all it consists of is 8 pages of text; one page of instructions, one page with the PAL equations to be burned into a PAL, four pages of diagrams showing where the jumpers go on the motherboard, and 2 pages showing before and after versions of the schematics. The upgrade hardware is one PAL, one capacitor and 9 jumper wires. It consists of adding the PAL into a blank IC slot, the cap above it, then running the jumper wires to the appropriate places. It's possible to do the entire upgrade without removing the motherboard if you directly solder the PAL to the board, I decided to install a socket instead, having all of the jumpers configured off of the socket and so had to remove the motherboard to solder the socket in properly. I did it in about 4.5 hours, being deliberately slow and careful, and had a buddy check everything I did after I re-checked myself a number of times. I used 30 gage wire-wrap wire, a 20-pin socket, and solder all from Radio Shack (the cap and PAL was supplied by a friend). The documentation says that the upgrade will only work with the 3.5 or later versions of the operating system, and I'm inclined to believe this from some guru's that told me about some driver masking mumbo-jumbo that was taken out of the 3.5 code. Before the installation, I was able to get a file system of about 50MB out of my CDC Wren II (86MB unformatted) when I used the "other" selection of the disk formatting menu from the diagnostic disk (3.51), telling it I had 925 cylinders and 8 cylinders/track (heads). I tried re-formatting, telling it I had 9 heads, and the format went fine, but errors occured afterwards. Then I did the upgrade and re-formatted again telling it I had 9 heads, everything worked fine, so I loaded up 3.51 and ended up with a file system of 63MB total! The neat thing about this is that BIG drives like the MAXTOR 190MB drive should be able to be fully utilized on the 7300/3b1 with this upgrade along with the WD1010 to WD2010 upgrade! There are no longer limits of disk drives with 1024 cylinders and 8 heads maximum on this machine! The VAR that I talked to in NJ has the MAXTOR 190 available, the demo line for them is 1-800-342-5029. Craig Votava [ihlp4!]looney!cmv /* End of text from looney:unix-pc.general */