vintage computing

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Testing MacOS on the Apple Network Server 2.0 ROMs
2 months ago
- Preproduction and NT ROMs for the Apple Network Server (ANS) were recovered from former Apple employees; the author had preproduction ROMs in storage.
- The '2.0' MacOS ROMs were tested on an ANS 700 using replica DIMMs, enabling internal SCSI and Cirrus Logic video support, unlike earlier ROMs that required external hardware.
- The 2.0 ROMs boot Mac OS from internal drives and support VGA output, but lack LCD activity, have a truncated startup sound, and omit proper device aliases for internal SCSI (e.g., scsi-int missing).
- AIX boot fails on the 2.0 ROMs (loader error) and causes system crashes, while the earlier 1.1.20 ROMs support AIX boot and have complete device aliases.
- Performance benchmarks show the 2.0 ROMs are significantly slower (3-5 times slower CPU/GPU, slower disk) compared to the preproduction ROMs and a G3 reference, likely due to missing L2 cache support and improper RAM timing.
- Rhapsody 5.6 boots on the 2.0 ROMs but crashes with a kernel panic due to interrupt issues; Mac OS X 10.0.3 and 10.2 lock up after startup.
- The preproduction ROMs (1.1.20) offer better performance and stability for Mac OS, but lack built-in ANS hardware support; the 2.0 ROMs seem unfinished and are not recommended for general use.
- Future work includes patching the 1.1.20 ROMs to fix reboot issues and attempting kernel patches for Rhapsody on the ANS.
Beej's Bit Bucket
2 months ago
- The article explores the hidden machine code embedded in a REM statement of the 1980s BASIC game 'The Wizard's Castle' for the Exidy Sorcerer, which was used to seed the pseudo-random number generator (PRNG).
- The REM statement's ASCII text actually encodes Z80 machine code when tokenized, with specific byte values like 0xED, 0x5F, 0x28, etc., forming a routine that reads the CPU's R register and stores it to a screen address for seeding.
- The code uses the R register (incremented frequently) to generate a random seed, retrying if zero, and stores it at screen address 0xF7FF, which is then PEEK'd by BASIC to seed the PRNG, limiting dungeons to 127 variations.
- Typing the code from the magazine listing likely failed due to non-ASCII glyphs; the author likely POKEd the machine code directly, using tokenized BASIC keywords that appear as odd characters when listed.
- The investigation involved disassembly, emulator testing (MAME, Java), and a tape image that confirmed the machine code, revealing how Sorcerer BASIC could execute hidden code in REM statements.
- The article provides a bonus token decoding table for bytes 128-255, showing how characters like 'F4' (0xC9) and 'S' (0xFF) map to BASIC tokens and non-ASCII glyphs.
Downtown Doug Brown
2 months ago
- Many old Quantum and Conner SCSI hard drives from the 1990s fail because rubber bumpers disintegrate into sticky goo, preventing the head from moving.
- The head gets stuck in the parked position; the drive spins up but cannot pass its seek test and spins back down.
- Opening old hard drives is possible in a clean environment; they are remarkably tolerant of dust exposure.
- A temporary fix for Quantum drives involves manually moving the head after the platters spin up, allowing the drive to complete its startup sequence.
- Conner drives may require more precise timing or a physical barrier (like Kapton tape) to prevent the head from resticking.
- Some drives have inaccessible bumpers under the platters, making replacement difficult; eBay offers plastic inserts as a solution.
- Data recovery is successful if the head is merely stuck and no catastrophic failure (e.g., head crash) has occurred.
- The author successfully recovered long-lost software from a Conner drive using these methods.
- Community contributions include ROM dumps, 3D-printed parts, and further insights into the issue.
On AI
2 months ago
- Author observed Andreas Kling's rapid coding with AI-assisted IDEs like Copilot.
- Initially skeptical of AI, author later adopted Claude and local models for coding tasks.
- Author embarked on a vintage Macintosh programming project, writing code only on original hardware.
- Projects include an IMAP email client, revision control, Wikipedia reader, IRC client, and BBS server.
- Author developed a modern web browser for classic Mac OS with TLS decryption.
- Author feels disillusioned by AI-generated (vibe-coded) projects that overshadow hand-crafted software.
- Despite frustration, author resolves to continue his work and be happy for community if AI tools are useful.
Sonnet Encore/ST G4: How a Tiny Capacitor Destroyed a Rare Upgrade
3 months ago
- The Workshop's Power Mac G4 MDD was in for cooling improvements, but a Sonnet Encore/ST Duet dual 1.8 GHz processor upgrade card suffered catastrophic failure due to an exploding tantalum capacitor.
- The explosion scorched nearby circuitry, rendering the rare aftermarket upgrade unusable, though the Power Mac's logic board survived and was later replaced with an official Apple dual 1.42 GHz module.
- Tantalum capacitors are generally reliable but can fail dramatically through thermal runaway, often due to manufacturing defects or stress, though such events are uncommon.
- The damage appears confined to power regulation circuitry, leaving the CPUs potentially undamaged, raising the possibility of repair by an experienced electronics technician.
- The article calls for skilled technicians to attempt restoring the rare Sonnet card, emphasizing the importance of rescuing vintage hardware and accepting challenging repairs.
Starlink from 1984
3 months ago
- StarLink was a hardware/software product announced by Digital Research Inc (DRI) in May 1984 that turned an IBM PC into a multiuser system supporting up to five users via terminals.
- The system included a board with an Intel 8088 CPU, 64KB RAM, and four RS-232 ports, running DRI's Concurrent DOS to enable multitasking and replace multiple PCs with one machine and inexpensive terminals.
- StarLink faced challenges such as high costs (priced at $1695, requiring a PC with 512KB RAM and a hard disk, totaling near $5000), compatibility issues (e.g., inability to run Lotus 1-2-3), and was not a commercial success, being abandoned by 1985.
Installing A/UX 1.1 like it's the 90s
3 months ago
- Successfully emulated and ran A/UX 3.1.1 on Snow, an emulator for vintage Macintosh systems.
- Obtained and archived A/UX 1.1 installation media (34 floppy images) from Dominic Sharp, addressing compatibility issues with Snow's emulation.
- Implemented support for the Macintosh II video card (Toby) in Snow to meet A/UX 1.x's hardware requirements.
- Fixed Snow bugs related to ADB keyboard modifier keys and NCR 5390 DMA handling during A/UX 1.1 installation.
- Installed A/UX 1.1 by partitioning, installing System 6, and using SASH (Standalone Shell) for bootstrapping.
- Installed A/UX 1.1 from 26 installation disks after fixing emulator issues, leading to a functional system with limited GUI support.

vintage computing

Testing MacOS on the Apple Network Server 2.0 ROMs

Beej's Bit Bucket

Downtown Doug Brown

On AI

Sonnet Encore/ST G4: How a Tiny Capacitor Destroyed a Rare Upgrade

Starlink from 1984

Installing A/UX 1.1 like it's the 90s