PC Speed: Atari ST Running MS DOS

The Atari ST was one of multiple home computers of the 1980s that came out with the Motorola 68000 CPU. While very capable indeed it lacked compatibility with the ubiquitous IBM PCs and PC clones of the era. The Atari ST already supported the FAT file system, so you could read and write regular PC floppy disks, but running MS DOS or MS DOS programs was a costly and slow process on the 68k CPU. So a German company by the name of Sack Electronic GmbH invented the PC Speed Emulator. A hardware assisted piece of kit that would solder directly onto the top of the Motorola CPU!

Refurbishing the C64C

Here is another C64! This time around it’s one of the later C64C, also called the C64-II. It sports a look similar to the C128 and the Amiga, and on the inside it’s also a bit different to my Breadbin C64s. This particular model is pretty dirty, and I hope that it comes with a short board, sporting the SID 8580, because I do not have one of those. And of course I hope that it actually works, because I got it untested! So let’s open it up, clean it and make it shine like when it came out of the factory!

Let’s Code x86 Assembly: 0x07 Text Mode Plasma

In this episode of our tour through the 8086 assembly language, we learn a few new opcodes and concepts CBW makes an appearance, as does the powerful XLAT for looking up values in … look-up tables! We use this to make a text mode plasma like effect. It is a bit simpler compared to what we did in another episode on the VGA card, but this time the executable is tiny, coming in at less than 170 bytes. We talk a bit about how to access screen memory in text mode and how to query the real time clock in the PC.

The C64 UfD Diagnostic Cartridge

There are many diagnostic cartridges for the C64 which can help troubleshoot problems with broken or dead C64s. This new cartridge comes with three special features: it measures the 5V rail, which can cause problems with the machine, it shows the CPU clock, which can be the cause for black screens, if absent, and it can run three different diagnostic ROMs. The C64 Deadtest, C64 Diag and C128 Diag are selectable via a small switch. Let’s assemble this new troubleshooting tool and test it out!

The HDD Clicker

Remember the clicking sounds of spinning hard disks? One “problem” with retro computing is that we replace those disks with Compact Flash, SD Cards or even SSDs. Those do not make any noises that you can hear under usual circumstances. Which is partly nice, because the computer becomes quieter, but also irritating because sometimes you can’t tell if the computer has crashed or is still working. This little device fixes that issue! It’s called the HDD clicker and it’s a very unique and funny little gadget!

Making Your own SEGA MegaDrive Cartridge

In this video I will show you how to assemble your own SEGA MegaDrive/Genesis cartridge, using an erasable programmable ROM chip, a so called EPROM. Those can be had for relatively small money, used on eBay, for example. You also need an adapter for the popular TL866II+ programmer, to be able to read and write EPROMs up to 32 Megabits (4 Megabyte) in size. This can be used to make your own repro cartridges of rare games, homebrew or demoscene productions.

The M396F 386SX Homebrew Mainboard

Marco Roth reverse engineered a broken M396F mainboard, powered by a 386SX CPU. This tiny Baby AT sized mainboard comes with six 16 bit ISA slots, four 30 pin SIMM sockets, a 40 MHz AMD branded 80386SX CPU and is a fancy purple color! Does it work? Let’s throw some soundcards and games at it and see how it behaves! Marco didn’t have a lot of cards to test with, so I offered to do it for him. Let’s see how it turned out!

Recording MIDI Music onto Floppies

I was asked by a viewer if the Roland SoundBrush that I showed in an earlier episode can also be used to record MIDI music from a PC. And yes of course, it can. With some caveats though! I connected the SoundBrush to my 486 PC and tried a few games. Lucasfilm games were running into buffer problems on the SoundBrush, but Sierra games were playing nicely. Let’s have a look and a listen how you can wire up the SoundBrush, format some floppies and record some MIDI files!