Click Here to visit our Sponsor
The Latest News ! The History of Computing The Magazine Have Fun there ! Buy books and goodies
  Click here to loginLogin Click here to print the pagePrinter ViewClick here to send a link to this page to a friendTell a FriendTell us what you think about this pageRate this PageMistake ? You have mr info ? Click here !Add Info     Search     Click here use the advanced search engine
Browse console museumBrowse pong museum


Ready prompt T-shirts!

see details
C64 maze generator T-shirts!

see details
Spiral program T-shirts!

see details
BASIC code T-shirts!

see details
Pixel Deer T-shirts!

see details
Shooting gallery T-shirts!

see details
Breakout T-shirts!

see details
Pak Pak Monster T-shirts!

see details
Pixel adventure T-shirts!

see details
Vector ship T-shirts!

see details



History of Jolt Serial One, Bill Ragsdale

I bought the first Jolt microcomputer out the door. I saw its advertisement (in Byte?) and was just starting a project in security access control. We were doing a crash project to demonstrate reading magnetic striped ID badges for Honeywell. We needed to accept a real-time bit sequence, extract numeric data and do a simple name vs. number lookup. An ideal job for a small processor. But remember, this was 1976. Development systems cost $5,000+ and none were offered for the 6502. (Later, MOS Technology offered one and Rockwell had a very good one.)

I ordered a Jolt system on a Wednesday or Thursday and was told Microcomputer Associates Inc.  (Manny Lemas and Ray Holt) was awaiting the first silicon of their DeMon monitor to come by air from MOS Technology in two days, on Saturday. DeMon was a one chip Debug-Monitor containing 1K of
ROM, 512 bytes of RAM, paralled IO, an ASCII serial interface and a monitor program. With the 6502 processor and a simple clock you could have a two-chip microcomputer. DeMon was later renamed Tim, Terminal Input Monitor.
MAI received their first DeMon chips about 9 AM Saturday morning, plugged in one, it ran, and I picked up the first unit at noon at their office. IIRC the Jolt had an inked-in serial number 0 or 1. Over the week-end I built a teletype interface as Jolt had a voltage output while the Teletype had current loop.

Either at that time or shortly later MAI expanded the line to a RAM card and an EPROM card using 2702 PROMS. The boards were about 4"x6," arranged in a vertical stack jointed by a ribbon cable. Only 5 volt power was needed. 

Our original programs were hand assembled and entered in hex via the Teletype keyboard. After debug they would be punched out as paper tape, again on the Teletype. Next came the need for an assembler. MAI had contracted for an assembler from a local programmer. The design and technique was very elegant: one pass from paper tape with listing, forward references resolved and a sorted symbol table, all in 2k bytes of PROM. The Teletype read the source code a line at a time. The text was converted into
object code in RAM with a listing printed. Forward branches showed as zeros in the listing but were resolved and a sorted symbol table printed at the end. We had to write in the forward branches on the listing by hand from the symbol table.

The programmer delivered the assembler three times, each time buggy and incomplete. MAI got me PROMS of each version. Bob Seltzer and I would try the release and submit bug reports. Along the way the programmer reported he was way over budget and time and was ending the project. Bob and I
eventually manually disassembled the assembler, fixed the bugs, punched a paper tape and used the buggy assembler, with workarounds, to assemble a clean assembler, then burned PROMS. I then wrote a line editor and donated it back to MAI.

In the course of software development I wrote my version of Forth on the Jolt using the assembler and paper tape input. Next I linked up a dual eight-inch PerSci floppy drive. With some jiggling I got the serial port to talk to an early CRT terminal (ADM-3) at 2400 Baud.  Next came a high-speed
paper tape reader and PROM burner. All this went into a large blue box. This became the development system at my company, Dorado Systems.  The Forth went on to be distributed as fig-FORTH by the Forth Interest Group. I was the first president of that group from 1979 until about 1984. My 6502
Forth was transported to the Apple ][ forming the basis for its first word processor, EasyWriter, written by John Draper.

Jolt was the first 6502 one board computer but soon was followed by the MOS Technology's Kim and the later Rockwell board. Manny Lemas and Ray Holt went on to merge MAI into Synertec and did the VIM/SYM one board computers. Dorado Systems used the SYM as the basis for 650 energy control systems for the Lucky food stores in the mid 1980s. Our 6502 products went mostly to Honeywell for door access control products used world-wide. Over time we migrated our development onto PCs but the blue box, Jolt based development system was our backup for development and PROM burning.

Click here to go to the top of the page   
Contact us | members | about | donate old-systems | FAQ
OLD-COMPUTERS.COM is hosted by - NYI (New York Internet) -