Recent content by JohnElliott

The tool I used under CP/M 3 was called U3.COM, and was invoked by U3 FILENAME user to move files between user numbers, or U3 FILENAME to unerase a file. It used the BIOS to access the disk directory, and rewrote the first byte of matching directory entries as the new user number. You can find...

As I recall: The hard drive power connector is a 3-pin Berg plug on the other side of the IDE connector from the usual 4-pin Molex, so if the hard drive doesn't have a matching 3-pin socket you'll have to come up with an adapter. The BIOS doesn't support a 'user' hard drive type, so if your...

dskconv is designed to convert the format of the container file (for example, from Teledisk to IMD) leaving the contents unchanged. So it could convert a 720k raw disk image to a 720k Teledisk file, or a 720k IMD file, but it can't convert a 720k raw disk image to a 1200k disk image in any format.

The school I attended in 1984 certainly had 1k ZX81s in the computer room, along with BBC Micros and one solitary Acorn Atom.

When I did this I made the cable myself. No soldering required; I got a 34-way floppy cable, removed the 34-way motherboard connector, pushed the end of the cable through the hole in the PC case, and crimped on an IDC 37-way connector. The gap for the three extra wires went on the side of the...

I wrote up this keyboard (or a very similar one) for my PC1512 page. If anyone wants a dump of the ROM, here it is (along with a partial disassembly, if you can read 8048 asm).

I've recommended DISASMV2 (DOS-hosted) in the past; it can be found at http://cd.textfiles.com/pslv4nv11/DOS/PRGMMING/ among other places.

The games pack looks similar to one of the two I had for the 5086, with the installer adding icons for the games to the empty 'Games' folder in the Counterpoint launcher. What I've never seen, but have a feeling there ought to have been, is a similar pack that populated the empty 'Business' folder.

If it's like the 2386, then the first 16k of ROM (mapped at 0xC0000) is largely zeroes, and the fourth 16k (mapped at 0xCC000) is 0xFF bytes.

Fascinating. It's a pity that there doesn't seem to be documentation for the FE2011 chipset online, bar a 2-page overview.

By way of contrast, SID starts the program being debugged with SP=0100h, so unless the program sets up its own stack there's a chance of it being overwritten by (for example) DMA to 80h.

There is no FDISK for GEM. GEM runs on top of DOS (or DOS Plus), and the FDISK on the PC1512 boot disk is the one for MSDOS 3.2. FDISK /MBR was introduced in MSDOS 5, so won't be available on the PC1512 unless you use a more recent version of MSDOS. Not quite. There is the possibility of a...

I had another look at the protection code, and searching for the sequence B2 02 B9 03 00 80 F2 03 and replacing the first two bytes by EB 13 should bypass it. But the resulting EXE still didn't seem to work on MAME - the problem may be some other part of the emulation rather than the copy...

Note that ddrescue and dd_rescue both exist. Of the two, I've only used ddrescue so can't say how they compare, but it seemed to do a good job with the failing hard drives I unleashed it on.

I think you're going to confuse people by using terms like "ATA". That refers to a type of hard drive connection with 40 or 80 wires in the cable, not a floppy connection with 34. (Also, the PC1512 dates from 1986 and ran MSDOS 3.2, and its display is not anything like MCGA, but that's by the...