niche 68K Mac emulation needs

black and white screenshot of Macintosh System 7 desktop showing Disk First Aid icon
It amazes me how you manage to live in anything that small“: actual size Mac Classic II screenshot

So I’m refurbishing the Mac Classic II I got in 2016 now that I’ve found that BlueSCSI is a fairly cheap way of providing large replacement storage. The 40 MB (yes, 40 MB) drive from 1992 can finally be replaced.

Hit a snag, though: DiskCopy won’t copy a disk with errors, which this drive seemed to have. DiskCopy also won’t repair the boot disk, so you have to find a bootable floppy or some other way to work around this limitation. The only readily available bootable disk image I could find was the System 7.1 Disk Tools floppy — which reported no errors on my drive! Later versions of Disk First Aid would fix it, but weren’t provided on a bootable image.

Here’s the 7.1 Disk Tools floppy with all of the apps replaced by Disk First Aid 7.2. Both of these were found on the Internet Archive’s mirror and combined:

Disk duly repaired, DiskCopy was happy, backup complete. Eventually: the Classic II is not a fast machine at all.

I love the old Mac icons, how they packed so much into so few pixels:

enlarged icon: stylized ambulance with flashing light and driver, side is a floppy disk, there are motion lines at back and the whole icon is slanted to indicate speed/rush
Disk First Aid icon

It’s a stylized ambulance with flashing light and driver, the side is a floppy disk, it’s got motion lines and the whole icon is slanted to indicate speed/rush. Nice!

Vaguely related: most old Mac software is stored as Stuffit! archives. These don’t really work too well on other systems, as they use a compression scheme all their own and are specialized to handle the forked filesystem that old Macs use. Most emulators won’t know what to do with them unless you jump through hoops in the transfer stage.

Fortunately, the ancient Linux package hfsutils knows the ways of these hoops, if only you tell it when to jump. The script below takes a Stuffit! file as its sole argument, and creates a slightly larger HFS image containing the archive, with all the attributes set for Stuffit! Expander or what-have-you to unpack it.

# sitdsk - make an HFS image containing a properly typed sit file
# requires hfsutils
# scruss, 2021-07

    [ $# -ne 1 ]
    echo Usage: $0 file.sit
    exit 1

# hformat won't touch anything smaller than 800 KB,
#  so min image size will be 800 * 1.25 = 1000 KB
size=$(du -k "$1" | awk '{print ($1 >= 800)?$1:800}')
dd status=none of="$dsk" if=/dev/zero bs=1K count=$((size * 125 / 100))
hformat -l "$base" "$dsk"
# note that hformat does an implicit 'hmount'
hcopy "$1" ':'
# and hcopy silently changes underscores to spaces
hattrib -t 'SIT!' -c 'SITx' ":$(echo ${1} | tr '_' ' ')"
hls -l

What this does:

  1. creates a blank image file roughly 25% larger than the archive (or 1000 KB, whichever is the larger) using dd;
  2. ‘formats’ the image file with an HFS filesystem using hformat;
  3. copies the archive to the image using hcopy;
  4. attempts to set the file type and creator using hattrib;
  5. lists the archive contents using hls;
  6. disconnects/unmounts the image from the hfsutils system using humount.

Notice I said it “attempts” to set the file type. hfsutils does some file renaming on the fly, and all I know about is that it changes underscores to spaces. So if there are other changes made by hfsutils, this step may fail. The package also gets really confused by images smaller than 800 KB, so small archives are rounded up in size to keep hformat happy.

In the very unlikely event that you want to repair a broken handset socket on a Princess telephone …

It seems that Princess telephones — like the one I have — were notorious for having their connectors break. The connectors are made of brittle thermoset resin, and sit just where they’d hit the ground if you dropped the phone. This is definitely what happened here:

Very broken 616p modular handset connector. Pins are (l to r): Black, Green, White, Red

For the handset, you want a 616P connector. If your wall connector has gone too, you’ll need the 623P connector for that. These are fairly readily available on eBay.

These instructions really only apply to the 2702BMG model of the Princess phone. There are many variants, and the 2702BMG was one of the last Princess models made.

  1. Remove the upper body by unscrewing the two screws at each end of the base

    Undo the screws at left and right to remove the case
  2. Remove the body, and remove the keypad. This is held in by two screws, one on each side of the keypad
  3. If your phone’s anything like mine, untwist the wires inside to get the line and handset connectors separated
  4. Unhook the old connectors from the terminals, and attach the new connectors as shown:

    Handset wiring: Green → S, White & Red → R, Black → T
  5. Slot the handset modular connector into its space in the phone chassis
  6. Replace the keypad
  7. Re-route the wires so they don’t get pinched or block the handset hook, then re-attach the plastic body with the two screws.


When you fix a thing and it just works …

When you fix a thing and it just works …
Skelf is a Scots word for splinter or shard and is a weak pun on the Stealth clips that splintered for me.

When both clips broke within a week on my Timbuk2 messenger bag, I knew I had to do something. This coincided with me fixing my 3d printer (it was the extruder feed: it was too loose all along!), so I was able to prototype a new clip.

clip section

The files are on Thingiverse: Messenger Bag Replacement 25 mm Webbing Clip, or there’s a local copy here:

big camera

Got the RB67 back from Kominek, and they did a great job. While it still looks a bit beat-up, everything runs silky-smooth. It did cost a bit more to CLA  than the camera cost to buy, but I’m very happy with what they’ve done.