ROGER Hi Ken. Was wondering if you're the same Ken Burgett who developed the OS for Intel development systems. If so, I have an interesting find I'd like to ask you about. -Roger from Texas KEN Hi Roger, I was Project Leader for ISIS, ISIS-II, and RMX-80. I am always interested in the history of software. Please send me what you think is interesting. ROGER Great to hear you are the correct Ken. ?? in the 70's I worked with MDS800 systems in Irving Texas. Recently I just purchased a used MDS888 system to restore and preserve. Much to my surprise, this system boots into a very interesting OS called OSIRIS V3.0 Nobody in the MDS groupie clan has ever heard of it. So it's caused quite a stir. I wrote some software to extract the HD and FD files over to my PC because I'm afraid this HD is going to crash. It's a 20mb 3rd party HD that went with the system. KEN Do you have any file names? ROGER The floppy is labeled "OSIMAN.300" and the system requires it in drive 1 to boot from the HD which gives a prompt OSIRIS V3.0 Our thought is this is either an interm version from Intel that didn't get out much or it's a 3rd part version to make use of a HD before that was mainstream. KEN That is a new one on me. I do wonder about the similar egyptian-sounding names. Isis and Osiris. ROGER It operates just like ISIS-II and it has all the usual file names ISIS.DIR, ISIS.MAP, etc ASM80, PLM80, LINK, LOCATE, the works there are 5-10 of us ole-timers who are keeping systems running and collecting software and documentation for preservation purposes. And because we think these systems are cool and we know them well. KEN My memory is not what it once was, but the names are very familiar. The software group moved from Santa Clara to Oregon in 1977, and I left the company. Any marketing or software work done after that was not done on my watch. I developed another OS for Nat Semi, called Starplex, but the file system was a complete redesign. If you could show me the boot disk file system, I might be able to comment on it. Just a list of files on the disk. ROGER Ok, I'm documenting all of this for the purposes of preservation http://www.rogerarrick.com/osiris/ On this page, just scroll down and there are links to text files of the directories, very easy to see. KEN I don't remember anything about a clock in the MDS800, and ISIS-II didn't have a clock. Osiris is much newer. ROGER Right. There is no RTC in this system hardware, so they must have just been using a timer interrupt. A signon message says "Remember to enter the time". Just like the first PCs KEN I had several MDS 800 systems, but didn't use any of the later systems with embedded CRT displays. That later system may have had a clock. ROGER Those were Series-II just after MDS800/888 KEN Right. I did some consulting with Intel while they were adding a cartridge disk drive, 20MB, I think. I made changes to the file system allocation table to handle the new drive format. ROGER Those were the Pre-MSDOS Fat days. Just know that there are a few enthusiast who use your OS :) KEN Yup. The original 8" floppy had 77 tracks, with 21 sectors per track. Both numbers are the product of 2 primes. There was no way I could justify multiplying and dividing within a file write, so we used a direct bitmap, with padding on each track. A file sector was identified by its track/sector pair. Couldn't afford a lookup table with a 12kb kernel. ROGER My system, unfortunately has the SBC202 Double Density controllers, so I can't read single density diskettes which I have. So I'm on the lookout for an SBC201 drive board pair. Intel used their own special double density format mmfm which is not very standard. KEN The floppy disk encoding format was probably picked by Bob Garrow, with input from an engineer named Mike (?), who actually designed and built the controller. We designed the whole system around Shugart drives, and then Marketing picked Control Data as the drive vendor. We had good reliability with Shugart, not so much with Control Data. ROGER I have the Shugart 800 drives, but the controller pair is the special double density mmfm. I remember the CDC drives with the little lever in the middle KEN I built a dev system out of SBC modules. An SBC86/30 board with 64k ram, an SBC 80/20, and a dual floppy box with controller. We configured the 80/20 to access the 64k ram of of the 8086/30. That system could boot ISIS-II, and CPM-80. By adding some PROM logic on the 80/20, we were able to boot CP/M-86, using the floppies, and getting its keyboard and screen output from the 80/20, which owned the video terminal and printer. It also could boot Starplex and we used it until the customer could finally provide us with a floppy disk controller. ROGER Wow. Would you mind me sharing some of this info with the others who are interested? KEN Well, signing off. This has been fun. Share what you like. ROGER Would you consider writing a short history of this? If so, I could put it online for everyone to see. KEN I will consider that. ROGER Ok great, thanks for all of this and take care. End of chat