Self Referential Pen Plotter Floppy Disks

In November 2021, I posted a short video on Twitter of my Roland DXY 1150 pen plotter drawing a generative wobbly circle design on top of a 5.25″ floppy disk. A few people responded that they would buy one of the floppies. This got me thinking about the medium of a floppy disk that I was using.

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Commodore PET 2001 Repair

(This was originally a Twitter thread from November 6, 2017.)

November 6, 2017

A huge box has just arrived! And inside are lots and lots of packing peanuts. Wait, wait, there’s something else in here. It looks like it’s from the future.

Say 10 PRINT”HELLO WORLD” to the Commodore PET 2001 from 1977, one of the “trinity” personal computers. Big thanks to @FozzTexx!

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Welcoming (back) a LaserWriter II

July 31, 2022

Welcoming a new (old) printer (back) into my fleet: a LaserWriter II. It’s a workhorse of a printer from 1988 dressed in Snow White design language. #RetroComputing

(This is an experimental post to attempt to convert a Twitter thread into a WordPress post).

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Hayes InterBridge

The Hayes InterBridge is “an inter-connecting ‘bridge’ that allows users of an AppleTalk network to tie into other AppleTalk networks.” This niche product was sold by Hayes in 1987 for $799 retail. There’s not a lot of information about this device left around so this page is an attempt to collect what I can find.

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Making DOS and CP/M 5.25″ Boot Disks with Commodore 128 and 1571 Floppy Drive

Did you recently get a new MS-DOS, KayPro IV, or Osborne 1 computer but no boot floppies?

If you have a Commodore 128 and a 1571 floppy drive, you might already know that you can read and write certain CP/M floppy formats while in CP/M mode. This is because the 1571 floppy drive can read and write two types of disk encoding schemes. GCR (Commodore, Apple, etc.) and MFM (common on CP/M and DOS platforms).

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Modern Upgrades for the Hayes Chronograph

Hayes Chronographs

Until recently, I had no idea what a Hayes Chronograph was. I didn’t even know it existed until Bill Lange (@BillLange1968) posted a picture of one on Twitter that linked to a wonderful article he wrote about them. The name Hayes was instantly recognizable though, being the inventors of the Hayes “AT” Command set that has found a way into just about every modem since. The shape was also familiar, a bigger version of the same case used in their Smartmodem 300. This was different. It had a beautiful vacuum fluorescent display (VFD) that was showing the current time and day of the week. I was hooked. I needed to buy this. What a wonderful trophy from the soon to come BBS halcyon days.

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Atari Portfolio Serial Interface: How To Get Terminal Software

I’ve had an Atari Portfolio HPC-004 for a couple of years now. It’s a slick little palm-top: solid state memory, MS-DOS compatible, 4 AA batteries as power source. It also has a docking slot on the right side for extra peripherals. This enables you to add communications ports that are otherwise lacking like a parallel or serial port. I’ve been seeking a second hand serial interface (HPC-102) for some time but have come up empty. I decided to instead purchase one new.

Atari Portfolio and Serial Interface
Atari Portfolio and Serial Interface
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Convert a Commodore 64 from NTSC to PAL format

If you’ve ever used a NTSC Commodore 64 for any length of time, you’ll quickly find out that many games and demos you try to run on your machine sometimes exhibit strange graphic or sound glitches or just refuse to run properly at all. It’s most likely because the program you’re trying to run was originally written on a PAL machine. With it’s different VIC-II chip generating a different master clock signal, the PAL C64 has a few more cycles available per frame than the it’s NTSC counterpart. Tightly coded loops in programs rely on a certain number of cycles to be available. And when they’re not, well, it doesn’t work as intended.

If you happen to own a C64 “short board” system, you can convert your NTSC machine to a PAL one easy. If you are unsure which board you have inside, you can open it up and take a look or make an educated guess by reading this site. A SID 8580 is usually a good sign you have a short board. But please make sure you confirm your board type before you begin. The VIC-II types (65xx vs 85xx) are not interchangeable!

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