Last updated Mar 20 2018. Edited by Herb Johnson, (c) Herb Johnson, except for content written by others. My thanks to Mark Thomas, who provided the bulk of this content, and who did the hard work to restore two DJ2D/B boards to operation with address PROMs. Contact Herb at www.retrotechnology.com, an email address is on that page..
In late 2017, I worked with Mark Thomas, who restored an IMSAI. This Web page is about the Morrow DJ2D/B boards he restored to use.
The typical confusion about this card, is where they are addressed in memory. Originally their ROM with boot code was addressed at E000H, with the card addressed higher. Many owners, or Morrow, changed them to F800H, either with a new address PROM or by rewiring logic around the small PROM. Mark decided to reprogram the PROM to change the address. Mark gathered from myself and others, boot and BIOS and FORMAT code for both addresses. Also he used a PROM programmer and struggled to find usable and programmable address PROMs. He's sharing those results with me, on this Web page. - Herb
Here's Mark Thomas's accumulated results in a ZIP file. These contain files, PROM dumps and IMD disk images, from Mark Thomas, Herb Johnson, and Mike Loewen as described briefly below, and in more detail on this Web page.
I"ve gathered some of the DJ2D/B schematics, because the boards have gone through some minor revisions. Here's a DJ2D/B rev 2 schematic PDF. Here's a DJ2D/B rev 4 schematic PDF. Here's a DJ2D/B no-rev schematic PDF. Here's a ZIP file of photos of Mark's Rev 0 and Rev 1 boards, and Herb's Rev 4 board. As discussed later below, Mark and I have not established which boards correspond to which schematics.
Some additional files are available from other Web sources, as noted below. - Herb Johnson
Mark Thomas says: "I have E000h ROMs and corresponding bootable IMDs with good format program and CBIOS source, and likewise F800h ROMs and corresponding bootable IMDs with good format program and CBIOS source. ... the README files provide most of the key information.
Obtained From Herb: [the folder with] README.TXT, DJ2D_E.IMD and DJ2D_E2.IMD disks have what looks like a Morrow part number on them, and both boot successfully in my E000h configured controller with what I believe are it's stock ROMs. Both had some bad sectors, but I used CP/M to create one hopefully non-corrupt disk using the good files from both. {Note from Herb: I added to this ZIP file, a disassembly of the boot code.]
Obtained From Mike Loewen: [I have a folder with] a bootable ImageDisk IMD file, board photo, and BIOS code. As per README.TXT, EXTSYSMM-F800.IMD boots on the F800h configured card of his. It is also of note that the CBIOS was modified for supporting 9 sectors/track using 1024 byte sectors, in addition to the original Morrow provisions. Mike approved my sharing this image and his notes.
Here are my [Mark Thomas's file] contributions. "DJ2DE000.IMD was created from the the files from the two Morrow images received from Herb Johnson. This is set up for a DJ2D @E000h with 56k RAM, SSDD 8-inch floppy [with format track 0 and 1 as 0/0: 500k SD - 26 sectors of 128 bytes - G1:7 G2:27 and 1/0: 500k DD - 8 sectors of 1024 bytes - G1:53 G2:116 . I believe I used MOVCPM to make this a 56k setup -- the original images from [Herb] booted a 24k CPM with BIOS @E000h. There's also photos of my rev0 and rev1 DJ2D cards." - Mark
The DJ2D/B has two small address PROMs and one 2708 boot PROM, at the chip locations listed below. The board was sold for operation at either E000H or F800H. So address and code PROMS are different for those configurations, as will be described below. The alternative to changing the address PROM 8C, was to rewire the board to change the address logic. The boot PROM 11D, has boot code assembled to run at the correct address locations. The list below, shows the "silkscreen" PROM model, and the "manual" lists alternative models of those addressing PROMs. Likewise, a bootable CP/M diskette, must have a BIOS and CP/M assembled and configured to run, with a DJ2D/B running at the expected memory address. Review the DJ2D/B manuals for further details, and the source files on the disk images provided. - Herb
3D silkscreen:6331 manual:MMI6331/82S123/74S288 8x32 PROM
8C silkscreen:6300 manual:MMI6300/6301/82S129/74S287 4x256 PROM
11D silkscreen:2708 manual:2708 8x1k EPROM
Here are Mark's ROM contributions. "3D-ALL.BIN is a binary dump of the PROM from location 3D, provided by Mike Loewen. This was identical to both [address versions of] my 3D ROMs, and so does not change to support different addressing. If someone has a failed PROM though, this dump would be helpful for replacing it.
"8C-E000.BIN and 11D-E000.BIN are binary dumps of the PROMs from location 8C and 11D from my believed "stock" E000h Rev 0 version of the card. My E000H 11D [boot PROM] appears to be "stock" Morrow based on the label. These work properly in both my rev0 and rev1 cards, using the disk-images Herb provided."
"8C-F800.BIN 11D-F800.BIN are binary dumps of the PROMs from location 8C and 11D from Mike Loewen; [for use of the board at F800H]. I believe these are as provided by Morrow, however his card did not have original-looking stickers on them so we are not 100% certain. These work properly in both Mike's and my cards, booting CP/M from Mike's EXTSYSMM-F800.IMD disk image. Note, the F800h CBIOS we have is set up for a Z80 CPU, so would need to be reassembled for an 8080."
About re-wiring addressing instead of changing PROMs, Mark says: "Although I found on the Web instructions for cutting traces and adding jumper wires to an E000h configured DJ2D, I wanted to be able to configure my card for F800h without having to make those physical modifications. I found discussion here about the 82S129 ROM contents, and how one might need to alter a [board with a] E000h chip to decode for F800h. But I saw no validation that someone had done this successfully. However the dump of Mike's 82S129 F800h address decoder matched exactly the speculative changes in the above posting.
As for programming address PROMs, Mark said: "In my DataIO 29A, I was successful writing 82S129 chips using the manual-listed DataIO 10/01 Family/Pinout. I successfully programmed some Fujitsu MB7052 chips from e-bay seller "arcadesurplus" using 78/01 Family/Pinout, once I resolved some issues with my programmer. These were somewhat chaper than 82S129 labelled ICs. I'm still not certain if I got some bad ones the first time around, or had dirty contacts on the programmer, but they are expensive things to waste when programming goes wrong." >
The world of old fusible-link PROMS is discussed by me and others, on this link-to "bipolar fusable PROMs" Web page. - Herb
Mark: "The disk images I have, as provided by you and Mike, seem to work flawlessly with both Rev0 and Rev1 DJ2D cards, in combination with the respective address decoder and BIOS PROMs copied from my card and Mike's. Both boot, and include a format program that works with the respective card setups. With thees files, provided you can burn the 2708 and 82S129, you can set a Rev0 or Rev1 card up for either E000h or F800h bios, and boot from provided images for either.
"We do not have an unmodified F800h disk image as might have been provided by Morrow, however the image from Mike is great, and one certainly can choose one of the more normal format options than the 9 sector/track option that had been added, or reassemble with those changes commented out. I found a few supposed F800h DJ2D disk images online, but none I found boot in my F800h cards, at least with the F800h ROMs from Mike. I speculate there may have been later Morrow controllers or these files might be mislabeled or corrupt.
Regarding my Rev0 and Rev1 cards, the Rev0 card has some factory added modifications, which I found were incorporated in the layout of the Rev1 card. I could find no other differences between the two cards, however of course I did not follow every trace..." - Mark Thomas
I"ve gathered some of the DJ2D/B schematics. Here's a DJ2D/B rev 2 schematic PDF. Here's a DJ2D/B rev 4 schematic PDF. Here's a DJ2D/B no-rev schematic PDF. I'm not sure how these "revisions" correspond to boards "rev 0" or "rev 1" from Mark, or my "rev 4" board. Here's a ZIP file of photos of Mark's Rev 0 and Rev 1 boards, and Herb's Rev 4 board.
The differences I see in the schematics, are largely in the early/late and VCO circuits which control data read and write timing from the 1771 FDC. On boards, I see some changes in PC board traces. Some boards you may find, might be hand-wired to incorporate revision changes; so look at any wiring changes against these schematics. Mark Thomas says his Rev 0 and Rev 1 boards work with the same ROM and BIOS software.
The DJ2D paper manuals included source listings for the boot ROM and for BIOS. Morrow's diskettes had sources for BIOS and FORMAT. There's DJ2D manuals at bitsavers.org under S100/morrow/cards, and at mabin.homeip.net under a similar directory or folder. Mike Loewen's site for his IMSAI work has links to his Morrow DJ2D files. Various archives of Rlee Peter's diskette archive "rlee" will have some files and sources. Mark Thomas has copied some of those manuals to his Web server. Of course I offer copies via my Morrow Web page.
In addition, Morrow provided a "regen" program. Some early single-density 8" diskettes were written in a format that was not the same as adopted later. This regen program will read such disks and reformat them, track by track. Read carefully the source code, don't damage your diskettes! But this may recover some disks you could not read before. - Herb Johnson
The "rlee" archive of many CP/M and related diskettes, is available from a number of Web sites. There's code and files for the Morrow DJ2D including the "regen" program. I've grabbed a few of Rlee's DJ2D sources and put them in this ZIP file. Check the CBIOS and FORMT against what Mark has put together.
Bitsavers.org continues to be "the gift that keeps on giving". Mark Thomas reports that another section
of the site has some useful disk image files. /bits/Morrow/decision/floppy has many disks images, but
disk image 509 (IMD file and ZIP of files) seems to be a copy of a Morrow DJ2D/B diskette with
code at F800H. Mark thinks these look "original". - Herb
This page and edited content is copyright Herb Johnson (c) 2018. Copyright of other contents beyond brief quotes, is held by those authors. Contact Herb at www.retrotechnology.com, an email address is available on that page..