Old Computer Challenge 2023, Day 1

My upgraded Rom switcher for the CDTV hasn’t arrived and neither has the desk for the CDTV. Instead I’ve decided to do the Old Computer Challenge on my MiSTer FPGA board. It feels weird doing something called the Old Computer Challenge on kit so modern, but I’ll be running an Amiga build so it won’t feel quite so weird.

To recap, the main things I want to get done this week:

  1. Process photos taken on a recent trip for the #CrappyCameraChallenge
  2. Look into the feasibility of a Spartan/Gemini server for KS1.3

I doubt I’ll get far into the second one, at least not without a ton of compromises. I’ve set aside a couple of hours a day over the week for working solely on this, but even if I only get as far as I did with my original CDTV setup, that’s fine too.

I’m using Amiga Vision’s A500 HD Build as the starting point for my setup. Before I packed it up for a move, my CDTV had 9mb of RAM, a SCSI2SD card for storage and SCSI Zip drive for transfer. I used a serial cable to link it to a Raspberry Pi for file transfer over UUCP, terminal access and to talk to a Pakratt PK-232 TNC for amateur radio comms.

I used the CDTV for all kinds of things, from writing for WhatIFF Magazine to casual gaming, including CDTV-only releases (some of which were actually pretty good for the time). I also started doing some light C coding, but since packing for the move in the spring I haven’t had a chance to sit down.

At the new place the CDTV will have a specific role more as an art station with a drawing tablet and Vidi Amiga 12 capture card. I have an upgraded 030/50 board to put in and this really needs a more modern kickstart. I wanted an “old blue” 1.3 machine for coding and doing 1.3 things, and tbh the new AGS setup provides exactly that.

The Setup

AmigaVision had an update in July, so I needed to copy it over to the system, then copy the A500 HD’s ADF file so I can use it without risking it being overwritten by upgrades.

I then tweaked the settings as so:

  • Switch display from NTSC to PAL
  • 68020, DCache On, ECS chipset
  • 2MB of Chip RAM, 384MB Fast RAM

I put a bunch of tools into the shared folder. Some are staples, some aren’t. I’ll go through them over the coming days. Most of the day was spent installing things, cursing when they didn’t work.

Starting The Challenge

I took my Kodak DC210 on a photowalk around Furness Abbey with a friend last month and had a bunch of photos to edit. These are all 640×480, which is at the upper end of what would be comfortable of a machine of this spec. Although the Amiga looks very powerful, it’s actually similar in raw performance to an original Macintosh or Atari ST, but with some of the overhead associated with it’s graphics and sound capabilities.

To start with I used Art Department Professional (AdPro) to load in the photos and save them as 24-bit IFFs. The Amiga uses a container format called IFF (Interchangeable File Format) developed by Electronic Arts back when they were a pretty cool company. The Inter-Leaved Bit-Map (ILBM) data layout was used for images, and stored each bitplane separately. Because I’m running Workbench 1.3 this is the land before Datatypes, and IFF-ILBM was the standard. I decided to use 24-bit IFFs for working with data, then I’d use AdPro to convert back to 24-bit JPEG images at the end of the process.

Everything on this level of Amiga is slow. Loading JPEGs is slow. Converting them to IFF is slow. Rendering them to screen is slow, saving them as 24-bit IFFs is slow. Be prepared to wait. The MiSTer’s 020 made things slow but bearably slow. Based on my experiences with my CDTV I suspect 68000 mode will be slightly less bearable.

Editing The Photos

Once I had 24-bit IFFs to work with I loaded them into a tool called True Brilliance 2.0. This is a really cool 24-bit image editor. It’s not like Photoshop and has a bit of a learning curve but Kevin Saunders’ YouTube channel and WhatIFF tutorials will get you on the right track.

I used a wide brush and set the paint mode to darken with a value of 5 and began touching up over-exposed areas. I can’t recover light data from JPEGs but it’s better than nothing. True Brilliance shows a 320 pixel wide view in HAM-6 mode, while working with 24-bit data underneath. This means you need to be patient, and that while images may give you an idea of how things could look, they’re not the same as the finished product. Everything felt magnified and it’s hard to get an overall view of the image. There is an Interlace mode option, but this is still 320 pixels wide due to HAM chipset restrictions. The image will look squished when using it.

After finishing my touch-ups I saved a separate 24-bit RGB IFF, but I wanted to see the difference between before and after. To do this I used HamLab Plus. This tool lets me take advantage of some non-standard Amiga features to generate close to or sometimes better than HAM quality at higher resolutions. I played around with the settings till I got what I wanted and saved it to disk. I then used the command line viewer Mostra to automatically cycle between images every few seconds to get an idea of the changes.

Once I was finally happy with the result I loaded the 24-bit RGB IFF back into AdPro and saved it as a JPEG. The MiSTer’s Amiga setup supports a shared filesystem which makes it much easier to get things on and off the machine.

I’ve put photos from today’s experiments on my fediverse account although this will disappear after 7 days. I haven’t paid for an upgrade to Bear Blog yet, but I’ll try to get round to it before the end of the challenge so I can upload photos to here in the vain hope someone else might like to give it a try.

Tomorrow I’m hoping to introduce ImageFX 1.5 to the workflow. ImageFX is another advanced photo editor that I use on my A4000. Hopefully the earlier version isn’t bad on a non-RTG machine. I guess we’ll find out.

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