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ExPLIT got a bit of a puzzle for me... His colleague has an Ericsson PC, and they tried to run my 8088 BIOS on it. Everything seems to work fine, except of the keyboard. I partially disassembled the INT 9/IRQ1 interrupt handler, and apart from typical PC/XT interaction with the 8255 PPI I/O...

I designed a battery replacement module for Compaq Portable III It uses replaceable CR2477N battery. Apparently, at 1000 mAh it is the highest capacity lithium cell battery one can inexpensively get :) Documentation and design files: https://github.com/skiselev/compaq-portable-iii-battery I do...

Recently it came to my attention that a Chinese company is selling 8088-based laptops on AliExpress. At least according to a screenshot posted on the AliExpress product page, it appears that the system runs a modified version of my 8088 BIOS (https://github.com/skiselev/8088_bios). The BIOS is...

I am trying to test and benchmark some of the ISA VGA cards that I have. Of course, something like this has been done before, for example see: https://www.vogons.org/viewtopic.php?t=57459, https://www.vogons.org/viewtopic.php?t=37844 and...

Hi, I have a 386DX motherboard with ALi M1429/M1431 chipset, and it doesn't boot at all... It doesn't show post codes, and looking at the CPU, there is no activity although it does seem to get the correct clock (CLK2 = 80 MHz). I still have to go through all the CPU signals, and figure out what...

Recently I've got this bug report on the 8088 BIOS. I'll describe the debugging procedure and other interesting findings for everyone's enjoyment. The bug reporter's observations were that SysChk utility hangs on a system with 8088 BIOS, but it works OK on the same system with GLaBIOS, so it...

Hi, I've released version 0.9.9 update for my 8088 BIOS, targeting Micro 8088, NuXT, and my earlier 8088-based projects such as Xi 8088. This includes several important fixes, including floppy code improvements, display issues with monochrome EGA/VGA, scancode fixes for several key...

Hi, A few people recently asked about connecting more than 2 drives to their PCs... So here is my answer - Monster FDC controller. (Of course one could install a second FDC card, but what is the fun in this?! Also there are not many cards out there that can be configured as a secondary FDC)...

Hi, I have a couple of Intel Professional Workstation (i486) systems that have an onboard 82596 Ethernet controller. I am wondering if a packet driver exists for this machine? Potentially I can take the Intel EtherExpress(tm) PRO LAN Adapter packet driver (eep10pkt_1102), which supposedly uses...

Hi, I am working on an ISA 8-bit (PC/XT compatible) Multi I/O board with the following features: 1. Floppy disk controller 2. Compact Flash interface 3. Two serial ports 4. One parallel port 5. BIOS extension / boot ROM (Flash ROM will be used) Obviously there is not enough space on the back...

Hi, Micro 8088 is the latest addition to my do-it-yourself IBM PC/XT compatible system series of boards. This board uses a fairly common Faraday FE2010A chipset, which is also used in the Commodore PC10-III, PC20-III and Colt, and apparently in the Intel Wildcard 88 module. Other than that...

Hi, I ran out of Zeta SBC V2 PCBs, and before I reorder them, I'd like to ask if anyone has any requests for fixes or updates to this board. Thanks, Sergey P.S. Here is the project page in case you're not familiar with this project.

Hi, A few people asked recently about an RTC card for PC/XT. I am wondering if it is something worth designing? Now to the technical aspect: I looked into several design options. Here are some of them: 1. Use Maxim/Dallas DS1501/DS1511 chip. Pros: - Chip is currently in production. The DIP...

I've bought a few Wildcard 88 cards a couple years ago in eBay. So I was planning to make a system around them, which got delayed due my other responsibilities and projects... Anyway, I found some time last two weekend to work on this. The preliminary description of the design is here...

I noticed that in many cases instructions like OR AL,AL and XOR AL,AL are used instead of CMP AL,0 and MOV AL,0. (AL can be substituted for any 8-bit register). While XOR has a useful side effect of setting ZF, OR reg8,reg8 works exactly the same as CMP reg8,0. I was assuming it is some kind of...

Hi, I tried booting FreeDOS (from here: http://www.freedos.org/download/; fdboot.img at the bottom of the page) on my Xi 8088 system. It hangs after printing FreeDOS123. While another (older?!) image from here: http://www.fdos.org/bootdisks/ - FDSTD.144.imz boots just fine. I am suspecting...

A year ago I upgraded a 286 motherboard that I bought from eBay. I replaced the on-board 1 MiB RAM with 4 x 1 MiB SIMMs, and more importantly upgraded the CPU from 12 MHz to 20 MHz. It is all not a rocket science. But I documented the process and posted the pictures here for everyone's...

Hi, I am wondering if anyone has/had the original IBM PC 5150 working with Trident TVGA8900 or TVGA9000 cards? How about IBM XT? (Not clones). Michael and I made a weird discovery that TVGA9000i based card that I designed doesn't work in IBM PC 5150/Retro-PC, but it appears to be working in XT...

I received XT-CF-Lite PCBs yesterday. I built and tested one board and it works properly. The PCB price is $10/each + shipping - $3 in US, $7 anywhere else. Let me know if you need multiple PCBs, so I can calculate the shipping. Note that I am offering just the PCB, you'll need to get other...

Today, in my quest to find ways for identifying various 8088 clones, I tested behavior of some undocumented instructions on several 8088-compatible CPUs that I have (inspired by this post). Processors tested: NEC V20HL (improved V20) Intel 8088 - Early 1978 version (one with MOV SS bug) Intel...