website/content/museum/heathkit-zenith-z-100-110-120.md

title, categories, types, origins, years, cpus, params

title	categories	types	origins	years	cpus	params
HEATHKIT / ZENITH Z-100/110/120	Computers	Professional Computer	U.S.A.	1982	Intel 8085	name company company_name specs tabs photos adverts links comments oc_id source Z-100/110/120 /companies/heathkit-zenith HEATHKIT / ZENITH label value NAME Z-100/110/120 label value MANUFACTURER Heathkit / Zenith label value TYPE Professional Computer label value ORIGIN U.S.A. label value YEAR june 1982 label value BUILT IN LANGUAGE Unknown label value KEYBOARD Full-stroke keyboard with separated numeric keypad and function keys. 95 keys. label value CPU Intel 8085 (8 bits) @ 5 MHz & Intel 8088 (16 bits) @ 5 MHz label value RAM 128 KB, up to 768 KB through 64 KB or 256 KB modules label value VRAM 64 KB (up to 192 KB) label value ROM 16 KB (boot + control tests), up to 64 KB label value TEXT MODES 80 x 24 + 1 independant line. (characters matrix : 8 x 9) label value GRAPHIC MODES 640 x 500 (semi-graphic mode with 33 special characters available), 640 x 225 (8 colors) - available with a color monitor label value COLORS 8 label value SOUND Built-in speaker label value SIZE / WEIGHT Z-120 : 49,5 x 49,5 x 34,3 cm / 22,7 Kg\ Z-110 : 49,5 x 49,5 x 18,1 / 18,1 Kg label value I/O PORTS 2 x RS232 connectors, 1 x parallel / Centronics connectors, S-100 bus connector (IEEE 696), phone/light-pen connector, 5 x expansion slots, RGB connector, Composite video output label value BUILT IN MEDIA 2 x 5''1/4 disk-drives (320 KB each) label value OS CP/M 86, Z-DOS, MS-DOS, Forth-Multix, Prologue label value POWER SUPPLY Built-in Power Supply Unit label value PRICE About $1,800+ - 7408 (France, february 1983) photos adverts links title subtitle text image Z-110 null title subtitle text image Z-120 null title subtitle text image Z-110 WITH MONITOR Z-110 with Zenith monochrome green monitor. null title subtitle text image SIDE VIEW null title subtitle text image RUNNING Z-110 running a ZBASIC graphic demo. null title subtitle text image OPENED **(1)** Switching power supply unit\ **(2)** S-100 slots\ **(3)** Floppy disk controller. The flat cable provides connection to an external 8" or 5.25" FDD unit\ **(4)** Dual full height 5.25" double sided, single density FDD's null title subtitle text image OPENED #2 Keyboard and floppy disk drives are taken apart. Note the add-on video card fixed to the motherboard. null title subtitle text image MOTHERBOARD **(1)** S-100 bus connectors. One of them is used for the FDD controller card\ **(2)** Intel 8085 processor\ **(3)** NEC V20 processor, 8 MHz compatible version of the 8088\ **(4)** 16 KB BIOS ROM. Holds both CP/M et MS-DOS BIOS's\ **(5)** Keyboard connectors\ **(6)** 768 KB RAM chips - 3 banks of 8 x 41256 + 1 parity chip\ **(7)** Video card connectors. null title subtitle text image USER'S MANUAL null title subtitle text image FRENCH ADVERT (SEPTEMBER 1984) null title url text Z-100 Life Line http://home.earthlink.net/~z100lifeline/ Great resource for Z-100 serie computers author date text Big al (St. Joseph Michigan) Friday 6th April 2012 An awesome machine. The Desktop 4 contract with the US government really hurt HeathKit. We ended up selling these computers below cost. The H-100 (Z-100) was one of the best computer we made. Baboo Rajaram really knew what he was doing. To bad they canceled the 286 version. Had the wire-wrapped 286 test machine for years. author date text John McLaughlin Tuesday 15th October 2019 My very first computer was an H100 with 256K RAM. I joke with students now that their watch has more current computing power. But for its day, it was a great machine. I wrote my PhD dissertation on it with Peachtext word processing software and a Toshiba dot matrix printer. author date text greg greene (Canada) Tuesday 23rd September 2014 Best keyboard for writing ever made ! still have mine with 8 inch drives !!!! author date text greg greene (Canada) Tuesday 23rd September 2014 Best keyboard for writing ever made ! still have mine with 8 inch drives !!!! author date text Dale Wilson (Saint Louis, MO) Sunday 14th September 2014 One of the best things about the Heath/Zenith computers was the technical documentation. Because they published schematics of their design I was able to get the tech sheets for the chips they used and use that to determine exactly how the graphics in the Z100 worked. Using that information I wrote Palette so I could take full advantage of their design which was far ahead of any other computer at the time. Although Zenith claimed 640 x 200, 8 color graphics, you could reprogram the chip to run 640 x 400 which worked just fine as long as your monitor could handle it. It was truly sad to see the IBM PC win the marketing war. author date text dstephens (San Francisco, CA USA) Thursday 27th October 2011 Started out with a Heathkit H100 remember all too well CPM and Z-DOS. I made the decision when building to not socket the chips and instead hard soldered to the board. Few years back I replaced electrolytic capacitors and resoldered every connection. Still have the system and it still boots up and runs fine. Software side getting IBM programs to run correctly was a challenge, that taught me I would rather work with hardware than be a programmer, it also gave a me a lot of respect for good programmers who can write "beautiful code" as an art form. Yes ran video in interlaced mode and managed to get RAM increased to 768K. There were plenty of hardware hacking projects for the S100 bus in Byte Magazine to keep the electronics technician in me happy. author date text Renee Rieser (Juneau, AK) Wednesday 14th September 2011 I was nuts about computers (well, Unix anyway, which is what I was using in college) and got engaged to my now husband over Thanksgiving in 1982. I had mentioned to my father that I''d almost rather have an H100 than a "real" wedding. Geez, BEFORE Christmas, an H100 was delivered to our apartment, along with dual 8" drives, a 300 baud modem, JT Turbo Pascal, ...I think we pretty much got the works of what was available both hardware and software. Of course it was a wee bit different than having a scaled down PDP in my living room, which is kind of what I had expected out of it. Soldering all the diodes and resistors onto the motherboard was interesting but more in a paint-by-numbers kind of way than using a breadboard. I didn''t know BASIC - but I learned. In fact, I learned a whole lot about PC hardware and software over the next few years, although what we had at school were PDPs and Vaxen (and a CDC 6500). Oh yeah, and I got married in the Tippecanoe courthouse in February 1983, with maybe 7 people in attendance. Somebody actually STOLE the H100, which I still used on occasion (CP/M) in the early 1990s, when our house got broken into. Heh. I''m sure they didn''t know what they were doing, but losing it that way makes me continue to kinda miss the old beast. author date text Dan Paladini (Switzerland) Sunday 15th August 2010 I bought my Z-100 low profile computer in 1983. It was years ahead of its time and was a brilliant computer to learn on. It wasn''t very IBM compatible, although a small percentage of programs for the IBM PC ran on the Z-100 out of the box. Most programs required a significant amount of trial and error "hacking" to run$ what better way to learn about microcomputers! I upgraded the 8088 processor to the hot NEC replacement core, raised the CPU to 7.5 MHZ via a daughterboard and did the wirewrap mod to use those new fangled 256Kbit memory chips to bring the memory up to 768K. Once I got the Video running in interlaced mode, I blew all my friends with IBM PC Color Cards away!\ Most of my programming was in Turbo Pascal and, of course, BASIC. This little gem launched my career in computers and kept me happy for the next 7 years until IBM PC Clones finally caught up to its capabilities! author date text Craig Carr (USA) Monday 18th January 2010 This was one of my very first work computers in 1985. I started my carreer in the engineering department and this was used for our CAD system. We were running I think ACAD 2.1 or 2.5 on Z-dos.\ Zdos was 80$ compatible with MS-DOS. We had huge color monitors on top of the systems. At least 25" displays and 16 colors. It was a great CAD system at the time. And I thought better graphics than the apple computers. I used to create lisp routines that ran within ACAD that would create custom batch that would do plotting as well as call up AutoCad again. Towards the end of the Z-100s, I had two of them in my office and I would start a command on one then swing around in my chair to work on another drawing on the computer behind me.. At this point I was too fast and kept both computers busy .. Fond memories author date text Paul Gautreaux (Louisiana) Monday 8th April 2002 My first computer was Zenith Data Systems Z-100 running at 4.77 Mhz with 128 kb on board, but I paid an extra $100 for another 64 kb...one bad machine. I bought it used...the guy could not figure out what to do with it. It had two 5.25" floppies and a built-in monitor. I came with about 50-bls of Z-DOS 1.0 manuals that were completely incomprehensable. I paid $2000 for it in 1981 and my wife still has not forgiven me. I had a modem that capped onto the phone with a connection rate of 300 bd. The only programs I had were those I wrote myself and I quickly found out I was not going to make my millions as a program developer...PASCAL still makes my skin crawl. I ended up getting a NORTHGATE 386 machine (backed another winner) and donated the Z-100 to our local library to be auctioned off. Some poor sucker ended up paying $300 for it in 1989. pmg 261 url date https://web.archive.org/web/20230417024943/http://www.old-computers.com/museum/computer.asp?c=261 2023-04-17

The Z-100 series professional systems were bi-processor computers. They used an 8-bit Intel 8085 to keep the CP/M compatibility and thus run a wide range of professional software, and a 16-bit Intel 8088 to run MS-DOS or IBM PC/DOS OS's

Two models were released: the Z-110 (pictured) which could display color graphics and was delivered with monochrome or colour monitor, and the Z-120 which had a built-in monochrome (green, amber or white) monitor.

Z-Basic was the only language supported by Zenith directly. It was an extra-cost option on most packages. It could handle colors and graphics.

The professional keyboard was quite complete with 95 keys, a separate numeric keypad, 7 editing keys and 12 function keys. All the keys could be redefined by software.

A wide range of expansions could be added to the Z-100. They came from Zenith directly, or from third companies, installed by dealers: one or two 1 MB 8" disk drives, 5, 10 or 20 MB hard disk, 64 and 256 KB memory modules, expansion card with 6 x RS232 connectors, analogue/digital conversion card, etc. The computer also had five S-100 bus connectors which offered a lot of possibilities.

The Z-100 was a very fast machine, one of the fastest in its category in fact. It was thus often used in a multi-user configurations, using Forth-Multix or Prologue operating systems.

The 8088 ran at 5 MHz initially, and then later at 8 MHz. The first boards could handle 192K RAM, but later boards could have up to (and use) 768K on the main board. The default Video RAM was 64K, but allowed 3 banks for up to 192K for full color.

The disk controller had support for four 5.25" and four 8" floppy drives, though OSs including CP/M and Z-DOS supported only two of each. The earliest models (pictured here) had full height, but later models had half height drives. There was a hack later on that allowed for four 5.25" drives under MS-DOS 2.x. A Winchester hard disk (5 or 10 MB) could also be connected.

These models were also available as the Heathkit H-100 series, sold then as kits. In these versions the monitor and video boards were preassembled, but user actually had to assemble the controller board and the analog video circuit on the monitor board.

Here are some software available for the Z-100 serie: CP/M 85, CP/M 86, MS-DOS 2.0, Prologue, Forth-Multix, Assembler, interpreted & compiled Basic, Pascal, Fortran, Cobol, C language, Forth, Condor file manager, DBase II, Multilog, JTBase, Infostar, Lotus 1-2-3, Multiplan, Supercalc, Wordstar, Spellbinder...