4am Profile picture
4am
to (de)protect and (pre)serve. he/him
Oct 28, 2021 13 tweets 7 min read
One of the improvements in the (unreleased) Total Replay 5 is a massive influx of super hi-res box art. @helix_nrg and other Apple IIgs fans have been on a mission to find, scan, and retouch the original artwork for Apple II games. A lot of people have fond memories of their favorite Apple II games, but have you ever even seen the original box? But could you pick the box out of a line-up? Did you even know they came in boxes?
Sep 17, 2020 21 tweets 6 min read
I spent some quality time reading the Essential Data Duplicator manual, as one does. This was the best bit copier ever written for the Apple ][. It received updates until 1993 (!) and never branched out into general disk/file utilities. It was what it was and made no apology.

1/
The manual is well-written, extremely technical, and pulls no punches. Here it accuses the author of Locksmith (another popular bit copier) of inventing and productizing a copy protection scheme, i.e. playing both sides.

2/ GENERIC BITSLIP COPY-PROTEC...
Feb 3, 2020 6 tweets 3 min read
Fraktured Faebles

archive.org/details/Fraktu…

Passport log: archive.org/download/Frakt…

Video: archive.org/details/A2Vide…

Thanks to @A2_Canada for the disk! title screenshot from flux visualization of Funny story about this game: it basically doesn't exist. The company was pivoting away from the Apple ][ right as it was going to production. The number of copies sold rounds to zero.
Dec 14, 2019 19 tweets 7 min read
Shortly after the release of Total Replay v2, @a2_qkumba and I embarked on a month-long refactoring binge, which eventually (d)evolved into the most ridiculous game of 6502 code golf you've ever seen.

1/
My first major refactor was to create the global variable gGameToLaunch and keep it updated. Previously, pressing RETURN would invoke a context-specific routine that figured out which game was showing on the screen, then launch it.
Nov 22, 2019 420 tweets >60 min read
Law of the West.woz

archive.org/details/wozada…

#wozaday title screenshot from "...gameplay screenshot from &q...gameplay screenshot from &q...flux visualization of "... Lane Mastodon vs. The Blubbermen.woz

archive.org/details/wozada…

#wozaday title screenshot from "...credits screenshot from &qu...gameplay screenshot from &q...flux visualization of "...
Nov 4, 2019 16 tweets 4 min read
Some notes on Buck Rogers:

First off, sectors on tracks are normally delimited by "sync fields" of nibbles that allow the disk controller code to get in phase with the nibbles, no matter where it starts. (It can't tell where it is within a track when it seeks to it.)

1/ "Sync" nibbles are usually eight "1" bits (0xFF) followed two "0" bits. Because reasons (read "Beneath Apple DOS"), this allows 6502 disk reading code to get back in sync quickly if it happened to start reading data in the middle of a byte, which happens most of the time.
Sep 20, 2019 7 tweets 3 min read
Story time.

In 1981, @jmechner tried and failed to publish an Asteroids clone for the Apple II. It looked like this: title screenshot from gameplay screenshot from 38 years later (so, this year), @a2_qkumba ported it to ProDOS and we included it in "Total Replay," our pack of 200+ Apple II games <archive.org/details/TotalR…>. Our version looked like this. gameplay screenshot of
Jun 9, 2019 7 tweets 2 min read
Mail's here "Complete in box" apparently includes Origin-branded miniature tools
Jan 25, 2019 8 tweets 2 min read
So here's a flux image of a typical protected disk by Sunburst Communications. Several things of note:

1. It is fundamentally a 16-sector disk. You can see the 16 sections of each ring (track), like an unprotected disk.

However... 2. On a regular disk, and even most copy protected disks, each sector is delimited by a stream of $FF nibbles. At a very low level, these are used to synchronize the disk reading routines after moving to a different track. On Sunburst disks, those delimiters are blank...
Sep 11, 2018 17 tweets 5 min read
Gather 'round, children, as I tell you the tale of Protect-O-Disk. Protect-O-Disk is ©1981 Bill Basham. Bill later got out of the copy protection business and wrote and sold a number of titles under the "Diversi" brand, including Diversi-DOS, Diversi-Copy (unprotected disks only!), Diversi-Dial, and the 16-bit Diversi-Tune.
Jul 25, 2018 250 tweets >60 min read
“A Woz A Day”

Apple II .woz disk images of copy protected software, verified in multiple emulators, full metadata, downloadable or playable in your browser. Also: raw flux files, visualizations, handcrafted screenshots, links to crack write-ups, &c.

archive.org/details/wozada… Hard Hat Mack.woz

archive.org/details/wozada…

#wozaday