reenigne
Veteran Member
Hi! My real name is Andrew Jenner. I'm a compiler developer by day job but I've been interested in old PCs for a while, probably because our family computer was an Amstrad PC1512 right up until 1994. After some 7 years of swapping floppies, I was pushing the limits of that machine in many ways.
One of the first games I played on that machine was Windmill Software's Digger. In 1998 I went on to disassemble, decompile and rewrite that game in C, resulting in Digger Remastered, a piece of software which (judging from the emails I received) may have led to the disposal of many old PCs which were being kept around just to play that game. The project spawned ports of the game to many platforms, a vicious high score competition, and (eventually) email exchanges with the original authors. It also got me introduced to Trixter, with whom I have had many enjoyable conversations about many aspects of Vintage Computing. I can't remember if he introduced me to this site or if I found it while looking for something else.
Since the Digger Remastered project, I've often thought that more accurate emulators would be a much better way to play these games the way they were meant to be played, and have (off and on) been dabbling with writing emulators ever since. I made some contributions to the PC drivers of MESS (most significantly some major improvements to the 8253 Programmable Interval Timer) which helped Digger work much better. However, what I really want to do is write a cycle-exact emulator for a IBM 5150 PC (or equivalently the IBM 5160 XT) with an Intel 8088, IBM CGA and PC speaker, and some software that pushes the machine so hard that it requires a cycle-exact emulator to run properly. That turns out to be really hard to do, so it's taking me a while.
To further this effort, last year I bought an old XT on eBay for $50 which I have been having a lot of fun with. Initially it had a bad RAM chip, a broken hard drive, a broken floppy drive, a broken ISA slot, a broken speaker, a broken power supply, no keyboard and a clone MDA card (the standard output of which can't be displayed by any of the monitors I have). Apart from that it works great and despite these hurdles, I still managed to write software for it, run it, and see and hear the results - an effort which got me some recognition from hackaday.com. I've now set it up so that I can send programs to it and get the results back remotely from other machines on my network, so I can perform timing experiments to further my emulator work from the comfort of my sofa. I got it reading disk images from serial and writing them to floppies last week so that I could help Chris Hafner bootstrap his machine (I think his floppies and drives are fine and he just has some bad RAM). My XT and I can sometimes be found at meetings of the Seattle Retro-Computing Society.
When I've had a spare moment I've been documenting my XT adventures and many other projects on my blog. Eventually I'd like to do similar projects for the other machines I knew in my youth: BBC Micro, Sinclair ZX81 & Spectrum, Commodore 64 & PET, Apple II, Atari 2600 and 800, Amstrad CPC and PCW and whatever else I come across that looks interesting.
One of the first games I played on that machine was Windmill Software's Digger. In 1998 I went on to disassemble, decompile and rewrite that game in C, resulting in Digger Remastered, a piece of software which (judging from the emails I received) may have led to the disposal of many old PCs which were being kept around just to play that game. The project spawned ports of the game to many platforms, a vicious high score competition, and (eventually) email exchanges with the original authors. It also got me introduced to Trixter, with whom I have had many enjoyable conversations about many aspects of Vintage Computing. I can't remember if he introduced me to this site or if I found it while looking for something else.
Since the Digger Remastered project, I've often thought that more accurate emulators would be a much better way to play these games the way they were meant to be played, and have (off and on) been dabbling with writing emulators ever since. I made some contributions to the PC drivers of MESS (most significantly some major improvements to the 8253 Programmable Interval Timer) which helped Digger work much better. However, what I really want to do is write a cycle-exact emulator for a IBM 5150 PC (or equivalently the IBM 5160 XT) with an Intel 8088, IBM CGA and PC speaker, and some software that pushes the machine so hard that it requires a cycle-exact emulator to run properly. That turns out to be really hard to do, so it's taking me a while.
To further this effort, last year I bought an old XT on eBay for $50 which I have been having a lot of fun with. Initially it had a bad RAM chip, a broken hard drive, a broken floppy drive, a broken ISA slot, a broken speaker, a broken power supply, no keyboard and a clone MDA card (the standard output of which can't be displayed by any of the monitors I have). Apart from that it works great and despite these hurdles, I still managed to write software for it, run it, and see and hear the results - an effort which got me some recognition from hackaday.com. I've now set it up so that I can send programs to it and get the results back remotely from other machines on my network, so I can perform timing experiments to further my emulator work from the comfort of my sofa. I got it reading disk images from serial and writing them to floppies last week so that I could help Chris Hafner bootstrap his machine (I think his floppies and drives are fine and he just has some bad RAM). My XT and I can sometimes be found at meetings of the Seattle Retro-Computing Society.
When I've had a spare moment I've been documenting my XT adventures and many other projects on my blog. Eventually I'd like to do similar projects for the other machines I knew in my youth: BBC Micro, Sinclair ZX81 & Spectrum, Commodore 64 & PET, Apple II, Atari 2600 and 800, Amstrad CPC and PCW and whatever else I come across that looks interesting.
