Vintage Computing

	Playing with S-100 Computers Links to entries for my various S-100 projects, including DIY boards, assembly of S100Computer.com/N8VEM hobby boards, and the restoration of my Cromemco Z-2D and CompuPro 8/16 systems.
	Digital Equipment Corporation Systems Operating and maintaing DEC computer systems, big and small. Ranging from embedded LSI-11/2 based systems to computationally "large" multiuser UNIX systems and physically large systems with core memory and a separate rack worth of external storage.
	Ohio Scientific Systems Started by a husband and wife team and ended by their divorce, Ohio Scientific produced interesting home and business computers in the 1970s and early 1980s. Restoration, maintenance, and related projects for my Challenger III triple-processor system.
	Sun Microsystems Founded in 1982 at Stanford University, Sun Microsystems produced UNIX workstations, servers, UNIX-like operating systems, and other software until their acquisition by Oracle in 2010. Their hardware lives on, sometimes still performing useful, modern tasks.
	XT-IDE Information and Projects The XT-IDE began as a VC Forums/N8VEM project to build an open source 8-bit ISA IDE controller and has progressed through several major developments. Here you'll find information on past XT-IDE runs as well as the new revisions and addons we're working on.
	Intel MCS-80 System Design Kit (SDK-80) Information and projects related to the Intel MCS-80 System Design Kit, or SDK-80. This was Intel's rapid development board for the MCS-80 family, which centers around the Intel 8080 processor. It provides a basic 8080 system with ROM monitor, which is interfaced over a serial link. Plenty of prototype area was provided for user expansion and experiments, making it popular in educational environments.
	R6501Q Single-Board Computer The Rockwell R6501Q processor has always intrigued me, but is nearly impossible to breadboard a computer with due to the QUIP64 packaging! With the recovery of ROM data from the Sontec FORTH computer, I wanted to design a single-board computer around the R6501Q to make use of some of the R6501Qs I'd acquired over the years.
	MTU Visable Memory Repair The MTU Visable Memory is a bitmapped video board for KIM-1 and compatible computers. It uses an 8K x 8 bank of DRAM in a dual-ported configuration, displaying the actual bit-for-bit contents of memory on the screen, rather than converting to characters or using graphics elements. This one was repaired for a customer.
	Ampro Series 100 Repair Ampro produced a well-known series of single board computers called Little Boards. The first was the Little Board Z80 and is of course Zilog Z80 based. They also made a chassis for this SBC, the Series 100. This one gets a full cleanup and repair.
	Shiva LanRover/E PLUS The Shiva LanRover/E PLUS is a fairly standard remote access/dialin/dialout/terminal server from the 90s. It requires firmware loads from the network but fortunately those files have been preserved! Let's take a look at some minor cleanup and repairs, and what it takes to bring up the LanRover/E PLUS.
	VA Linux FullOn 2x2 Server Cleanup This server was the first "proper" server I owned. It was bought cheaply online, a leftover from the dot-com bubble. It sat unused for many years in my parents' basement, now it gets cleaned up and put back to work.
	Sontec FORTH Computer ITI Audio/Sontec is known for analog audio mastering equipment. During the 1980s, they designed and prototyped a series of FORTH computers intended to control a mastering product which was eventually cancelled. This writeup takes a look at some of the extant prototypes.
	KIM-1 Boards of the Past In Summer 2008, I was working for a surplus components dealer while on break from college. I came across a number of KIM-1 systems, all which have been sold by this point. Here's a look at those systems.
	Miller Technology M80 Single Board Computer Cleanup, repair, and testing of a Miller Technology M80 single board computer. This little SBC is Z80 based, includes ROM, RAM, and parallel I/O, and could be supplied with a ROM monitor which bit-banged serial using some of the GPIO.
	Identicon 8080 Processor Board Identicon produced a wide range of barcode scanning equipment starting in the 1960s. Their products eventually included microprocessor control, one of them must have used this Intel 8080 based processor board. Sometime in 2012, a friend acquired several of these boards in a scrap lot, and we hacked on them.
	Hand Built Z80 System This hand built Z80 computer was purchased from a friend at VCF East 2018. He'd found it at an estate sale in Albany, NY. It is an interesting and very well-built system.
	Kaypro II Repair I've had this Kaypro II since 2010. It was a local pick-up deal and came with documentation, software, a Kaypro-branded Diablo printer, and even the black faux leather carrying cover! The machine had been stored very poorly, and is only now fully functional.
	Omega Micro Systems OMS-02 6507 Single Board Computer Bill O'Neill traded me one of his OMS-02 6507 based single-board computer in 2011 for one of my 8085 SBC rev 2 bare boards. We'll take a look at it, clean up the original build a little, and do some 6502 development with it.
	Alspa ACI-2 CP/M System The Alspa ACI-2 is a somewhat uncommon integrated CP/M system. At first glance, it appears to be just an external drive box for 8" floppy drives; however, the enclosure contains a full Z80 system with 64K of RAM and three serial ports! It's pretty quick, and the disk controller handles double-density, for around 600K per disk.
	Fixing the HP 700/43 Terminal A recent equipment pick-up had included a HP 700/43 serial terminal with keyboard. The terminal appeared to work, but the power button wouldn't stay latched in the on position, a common problem especially with vintage CRT monitors and terminals. The terminal was disassembled to replace the switch, which actually ended up being repaired instead. While open, the RIFA line filter "smoke caps" were also replaced, and everything cleaned.
	SIIG MiniSys S286 Small Form Factor PC I'd been casually looking for a SIIG MiniSys S286 since about 1998. The S286 is a 286 AT-compatible PC about the size of a narrow shoebox. With onboard IDE, floppy, VGA, serial, and parallel, and a single 16-bit ISA slot, it's a fairly useful AT-class machine in a very small box!
	Fairchild F8 Evaluation Kit The Fairchild F8 Kit was Fairchild's engineering evaluation tool for the F8 CPU set. The F8 has an interesting architecture, it's a CPU produced on LSI chips, but it requires more than one chip. This F8 Kit came in a heap of scrap and was a complete basket case when acquired. It now works once again.
	GW-1244-1, a Maintainable Replacement for the Dallas DS1244 32K NVRAM/RTC A piece of legacy networking hardware was losing its NVRAM on poweroff, and turned out to contain a Dallas DS1244 NVRAM with Phantom RTC. This module is still made, but is expensive and has its lithium power source potted in the module. Rather than buying an unmaintainable replacement, I designed a compatible replacement module.
	Rebuilding the Dallas DS1387 RTC/NVRAM Module A 486 industrial computer on the repair bench had a dead DS1387 RTC/NVRAM, which is no longer produced. The DS1387 is a potted module containing a DS1385 IC, a crystal, and a lithium cell. Over time, the lithium cell dies, and the module will no longer keep time or NVRAM contents. Fortunately, others before me had figured out the locations of the buried battery pins and provided their solutions. Here's my fix!
	Building a Lego TC Logo 9767 Interface The VCF Museum at InfoAge Science Center recently acquired a Lego TC Logo kit. While it included the IBM PC compatible ISA interface, the Lego 9767 interface card was missing. Fortunately, it is a simple card and is already well-documented on the Internet. A good excuse to lay out an Apple II protoboard though!
	Cromemco CDOS Tools With a Cromemco 4FDC and no boot media, getting a functional system was not entirely straightforward. Tools exist for bare-metal bootstrapping CDOS with a 16FDC, but they're incompatible with the 4FDC. Fortunately, there was enough existing work and experience in the area to hack together a solution!
	External 5.25" Disk Box This disk box was purchased to serve as a universal disk box for various projects. It came without drives and required a bit of creativity to safely mount both linear power supply boards.
	48 Hours of Apple IIe Hacking I finally got time to play with an Apple IIe I'd picked up cheaply. Getting CP/M running with a Microsoft SoftCard clone was easy...but getting new files to CP/M wasn't!
	Walnut Creek CP/M Archive CD-ROM via BitTorrent A friend of mine sent me a full image of the last Walnut Creek CP/M archive distribution on CD-ROM. I've created a BitTorrent tracker for it and uploaded it on 25 October 2010 -- 16 years from its release.