Lo-tech ISA CompactFlash Adapter — XT-IDE Storage Solution
The Lo-tech ISA CompactFlash Adapter is an open-source 8-bit ISA card that enables modern CompactFlash storage on IBM PC XT, AT, and compatible systems. Paired with the XTIDE Universal BIOS, it provides silent, reliable mass storage for vintage computers using inexpensive CF cards. The design uses only five through-hole ICs, making it accessible for home assembly. Originally designed by James Pearce at Lo-tech, with hardware schematics and BIOS source code freely available.
- Bus Interface
- 8-bit ISA (fits any PC/XT/AT 8-bit slot)
- Storage Media
- CompactFlash Type I/II via 40-pin IDE header
- I/O Address Range
- 300h–31Fh (300h–30Fh active)
- ROM Address
- C800h (32 KB window, directly flashable in-system)
- Flash ROM
- SST39SF010A 128KB (32 KB used) — in-system programmable
- Compatible Flash ICs
- SST39SF010A, SST39SF020A, SST39SF040, AMIC A29010
- Supply Voltage
- 5V from ISA bus
- IC Count
- 5 through-hole DIP ICs (basic build)
- PCB
- 2-layer, ISA form factor, through-hole only
- BIOS
- XTIDE Universal BIOS — GPLv2, supports up to 4 IDE controllers
- Transfer Modes
- PIO-8 (standard), PIO-8 BIU Offload, PIO-16 BIU Offload
- Max Drive Capacity
- Unlimited with MS-DOS 7.x/FreeDOS; 8.4 GB limit on DOS 3–6
ELKS - Embeddable Linux Kernel Subset
Introduction
ELKS brings a Linux-like OS to 16-bit Intel x86 hardware (8086/8088, 80286). It provides a multitasking, multi-user environment with TCP/IP networking on machines from the 1980s.
- Runs on genuine 8086 processors
- TCP/IP networking (NE2K, WD8003, 3C509)
- MINIX and FAT filesystem support
- Can boot from floppy disk or ROM
Turbo Clock Switcher - Engineering Application
Clock profile switcher for timing-sensitive software and test harnesses, enabling controlled transitions between true legacy rates and turbo operation.
- Profiles
- 4.77MHz, 8MHz, 12MHz, board turbo
- Switching Logic
- Debounced hardware line with deterministic latch state
- Feedback
- Status LED map plus software verification hooks
- Compatibility
- AT clones, 386SX, selected 486DX boards
- Use Cases
- Cycle-sensitive DOS software and diagnostics harnesses
- Field Harness
- Front-panel and relay control compatible
