MIT Swapfest walk through for May 19, 2024. Things that caught my eye! Lots of retro computing today, some radios, some Arduino lots of laptops and phono equipment and LPs. #retrocomputing#hamfest#mit#cambridgema#swapfest
minimod 1.2 is out now. Improvements and fixes are:
Only the sample data is loaded to chip memory now, other data will use fast memory when available.
Implemented OS friendly CIA timer interrupt setup, resulting in far improved stability, especially with Kickstart 1.x. This also fixed some of the playback glitches which likely resulted from the direct CIA poking/peeking that used to conflict with the OS itself.
🎇🏛 Today we are celebrating INTERNATIONAL MUSEUM DAY 2024! In collaboration with #ICOM Slovenia, we'll be hosting a vibrant program, including free entry to our permanent and guest exhibitions and three workshops for children and adults.
More Fun Making It is a video channel about fixing and restoring old computers and consoles, especially the ZX Spectrum, Commodore 64, Amstrad CPC etc. You can follow at:
Ever wondered why on #mc68000 a short branch to the next instruction will generate and error when assembling it?
bra.s .next ; will error out
.next:
The offset in the short branch instruction encoding is a 8-bit signed integer. Offset 0 (next instruction) is magic: that actually indicates a "wide" branch instruction with 16-bit offset following the instruction opcode. The offset 0 was of course chosen because branching to the next instruction is kind of pointless.
To actually branch to the next instruction you need to use the "wide form" branch:
bra.w .next
.next:
This instruction encodes to hex "6000 0000". Split down it is:
"60xx yyyy"
...where 8-bit offset xx is 0, which leads the instruction to be decoded as having 16-bit offset word yyyy. This offset word can have any value, including 0 => branch to next instruction.
On #68k CPUs instructions are always aligned on 16-bit - executing instructions at odd address is always illegal. Yet bcc.s and bcc.w can encode such branches.
So why didn't the CPU designers go for an implicit 2x multiplier for the branch target? This would have allowed branching from -256 to +254 for .s form and from -65536 to +65534 for the .w form. This would have effectively doubled the "reach" of the branch instructions and resulted in clear saves (for example being able to use bcc.s more often without having to resort to the bcc.w).
If you remember a time when using floppy disks didn’t seem weird, you’re probably at least 30 years old. Floppy disks or diskettes emerged around 1970 and, for a good three decades or so, they were the main way many people stored and backed up their computer data.
However, it’s now been over a decade since the last floppy disc was made, and it wouldn’t even have enough capacity to store a modern smart phone picture. So why do some people still love using them? BBC Future speaks to some of the floppy disk faithful to find out.
Received a new box of documents from Yaakov Kirschen in Israel a few days ago for use in my ongoing research project into his computer software.
Some of these documents are really sad, including a handwritten letter from his wife Sali to a creditor where she explains that they can’t repay a debt. Their projects generated almost no income, and they had spent all their savings to fund it.
Last night I was scanning some documents Sali Ariel sent me from Israel, when I found two small things I overlooked last week. They had gotten stuck in the box:
Cards with phone numbers for Jack Tramiel and Nick LeFevre of #Atari! 🗂️ 📞
Tramiel's card has three numbers: his "direct" line (presumably his Atari office?) and personal numbers for homes in California and Toronto.
Coffee + other substances = started yet another wilderness roguelike on the Atari 8-bit. Could work on Speccy game instead, but my idea felt more Atari, tho right now it looks like every other wilderness roguelike you've seen me make. Think more Archon, less deep. #atari#retrocomputing
Up until the end of the 2.6 era or so, the #Linux kernel had relatively few options to set. You could reasonably go through the configurator and set up a fine-tuned build for your machine in half an hour or so. This 2.2.5 kernel from Debian Slink has only 324 options, and the tree takes up a bit over 50 megs of disk space.
In 1994, our puzzle game Clockwiser was released for Amiga (OCS and AGA), CD32 console, MS-DOS and Windows 3.1.
This is the title sequence tune by our composer Ramon Braumuller, created with our own Digital Mugician Amiga music editor, published by the British Thalamus in 1990.