stan.rice%rand-relay@sri-unix.UUCP (11/07/83)
From: Stan Hanks <stan.rice@rand-relay> A friend of mine recently acquired an ancient IMSAI in the throes of decrepitude. Rather than pitch the CPU and re-populate the bus, he has elected to retain the current card set and "enhance" it. Problem with this particular machine is that it has no FDC; the current mass storage is a Tarbell cassette interfacer board (remember when that was about as good as a home hacker could do?? sigh....) Anyway, as this is a pre-696 machine, he is wondering what controller he can attach to it without having to really modify either the FDC or the CPU/memory/whatever. The optimal solution will be a 5.25/8 controller that will do everything from SSSD to DSDD; he will settle for 8 inch DSDD. BIOS for CP/M 2.2 is helpful but not required if sufficient documentation is available. Any help will be greatly appreciated. Please reply directly to me; I'll summarize to the list if sufficient response is made. Thanks much! Stan Hanks Department of Computer Science Rice University Houston TX stan.rice@rand-relay (arpanet) stan@rice (csnet) ...!lbl-csam!rice!stan (uucp)
w8sdz%brl@sri-unix.UUCP (11/08/83)
From: Keith Petersen <w8sdz@brl> Stan, I use a Morrow DJ2D floppy disk controller with two 8" drives. It allows double-density double-sided (1.2 megabytes on one 8" disk!). It comes with CP/M 2.2, Microsoft Basic-80 (MBASIC 5.21), and source code for the CBIOS. If you use the memory-mapped console port on the FDC board, you can bring up CP/M immediately without having to do any CBIOS configuration. The FDC uses memory-mapped I/O and comes standard with a starting address of E000h. There is an option (I recommend it) to have F800h as the starting address. This would use up F800-FFFFh which isn't too bad. Dave Hardy has modified his DJ2D to bank switch, thus allowing it to reside outside of the main system RAM, but this requires a modification to the CBIOS software. The DJ2D uses CPU transfers instead of DMA, so it does not conflict with other boards that use DMA. Mine has been used sucessfully with both an IMSAI-8080 and a generic S-100 box that has a Cromemco ZPU (Z80 CPU) card. I do NOT use dynamic memory because I've had problems with it when using the Z80. --Keith