MBECK@AI.AI.MIT.EDU ("Mark E. Becker") (06/25/88)
Hello Netland (spoken in a Glum Voice) - Not too long ago I picked up one of these Mylex 386-based AT style machines. Very nice. Runs everything like crazy. I've only seen two pieces of software that wouldn't run on it (apparently a victim of 8088/8086/80286-only type instructions). Now for the Fun Part. It used to be that, if someone had a disk drive whose geometry wasn't in tables, it was easy enough (for the hardware types) to patch the ROM and re-calculate checksums so as to get the most out of the drive without having to mess around with those programs designed to "fix this problem". The Mylex board uses the AMI-386 BIOS rom set. This set consists of four ROM's, a total of 128 KBytes. Bar none, this thing has about the most sophisticated built-in SETUP program ever devised.. drop down menus, software to test everything in the box, software to help determine the optimum interleave for a hard drive.. test floppy drives.. it'll even format floppies for you. Everything including the kitchen sink. The checksum algorithm is different than in "standard" ROMs. Telephone calls to AMI have resulted in a quiet silence to my questions; the checksum algorithm is "proprietary". I am quietly peeved.. In every flavor of computer I've ever worked with in the past, requesting information about machine insides after purchase one has either (a) been given away freely or (b) required me to sign a non-disclosure agreement. The thing isn't going anywhere.. it sits on my desk at home, letting me have fun with the MS-DOS world. I even have a small second drive wired up to it so I can tinker with MINIX. AMI's technical people have a good product (int 19 doesn't seem to work "right".. but I'm told that is a common problem) and the supplied documentation it is more than I've seen from anywhere else. Sigh. Just another hacker wishing for a return to the "old days". Suggestions? Mark Becker Disclaimer: These opinions are _mine_ and do not necessarily reflect those of the people running this computer.
syd@dsinc.UUCP (Syd Weinstein) (06/29/88)
In his note, Mark Becker complains about the AMI bios as not handling odd geometries. Please note that this bios has a special entry for odd geometries that handles and non standard one. Note that one entry, the last one, is empty. If you select this one it prompts you for all the parameters and I have used it to play with my disk to see if it had any extra tracks. It also handles my RLL controller this way to handle the extra sectors. It works fine. You don't need to mess with the checksum or change roms at all. (I have the same Mylex board) -- ===================================================================== Sydney S. Weinstein, CDP, CCP Datacomp Systems, Inc. Voice: (215) 947-9900 {allegra,bellcore,bpa,vu-vlsi}!dsinc!syd FAX: (215) 938-0235