My Background Is Real :-)
(you can click on most of the equipment above to go to the section that describes it)
(devices added after this page was last updated can be found here)
The first three computers are reproductions of computers that have sentimental value for me (all function just like the originals - same software and timing).
- DEC PDP 8/I - yellow lights - The 8/I was the first computer that I ever used back in 1971. The one here is running TSS8 (DEC's 17 user time sharing system for the PDP8). The PDP-8/I was a 12-bit computer and supported up to 32K 12-bit words
(48KB) of memory. It had a number of optional components including KE8/I the extended arithmetic element which added hardware multiply
and divide instructions!
- DEC PDP 11/70 - red lights on the top - The 11/70 was the computer that I used to learn Unix in college in the late 70's. The first officially named version of Unix ran on the DEC PDP 11.
- Altair 8800 - red lights on the bottom (1974). This was the computer that I wanted to build in High School but couldn't afford. I did build an IMSAI 8080 in 1976. I later designed/built various interface boards and drivers (keyboard, IBM Selectric I/O, etc) for it.
- HP 1000E front
panel is from a 16-bit Hewlett Packard computer. I worked on HP 1000E computers in the late
1970's; it was the embedded processor in HP's
78220
Arrhythmia monitoring system - a system that (IIRC) monitored 24 CCU
(coronary care unit) patients in real time -- watching for PVCs (premature
ventricular contractions),
ventricular fibrillation, etc. This was a micropgrammable machine and we
wrote custom microcode to aid in the signal (FFT related instructions) and data
processing (linked list related instructions).
There are two tape drives:
- White reels - DEC TU-55 (up to 250KB/DECtape). The TU-55 was the tape drive on the PDP 8/I that I first used. The circuitry in this unit was PC boards plugged into a
wire-wrapped backplane.
- High speed paper tape reader (paper tape had a density of 10 bytes/inch)
The Teletype is an ASR-33 (probably the most popular model that Teletype ever made). Note that this terminal only had UPPER case letters! The ASR-33 ran at 10 characters/second (110 baud) and could read and punch paper tapes. Trivia: The ASCII delete character is 0x7F because it allowed any character on a paper tape to be deleted by punching all 7 holes (paper tapes are 8-bits wide, but ASCII was a 7-bit code).
The black device with the red stripe above the paper tape drive is a Memorex 550 8" floppy drive that could store 1.2MB on an 8" double sided double
density 8" floppy. This drive is the actual drive that I used on a computer back in the early 1980's. The little notch on the bottom right is for write protect (covered with light-tight tape was write enabled, open was write protected).
The plugboard is from an old IBM computer. For
more information about plugboards check out Wikipedia and this site. My first job was working in a school datacenter; we used punchcards for attendance (among other things). We programmed plugboards to sort/select attendance cards based on what we wanted to know.
The core memory board is from an unknown computer and is 256 bytes (yes BYTES) of memory (see Wikipedia)! Each bit is a single ferrite bead (magnet). These were hand woven. Each of the 8 blocks is an array of 16x16 (256) beads. Core memory has the neat property that it is non-volatile (values in memory remain when the computer is powered off). Trivia: "core" files are called core files because early computer systems would save a copy of what was in memory (core) in a file after a crash.
The HP25C
was the calculator that I really wanted (but never got in college). Three
or four years after college I was chatting with a friend (Charlie Elliott) one
day and mentioned the HP 25C - a few years later Charlie found one at a yard
sale and sent this one to me :-)
For those old enough to remember, the
slide rule was the
"mechanical calculator" that was in common use before electronic calculators.
I've had this one for a long time and I had a circular slide rule in my car for many years to calculate gas mileage before cars did it
for you.....
Edison
bottles are not really computer tech, but they are cool, so I have a couple
displayed here :-)
The tape drives and teletype aren't connected.....yet.
On the rack behind the Teletype are paper tapes, DECtapes and 9-track tapes. The red write ring was placed in the back of a 9-track tape to write-enable the tape.
The vacuum tubes (aka valves) are actually old radio tubes, but are similar to the tubes used in early computers (before transistors, which were before IC's). See Wikipedia for more information about vacuum tube computers.
3D Printed IMSAI - a gift from my wife - those of you who
know me know about my IMSAI and our first date....

Vacuum tube robots - a gift from my wife

The candlestick phone is an original phone from the early 1900's. It's marked "Western Electric, Made in USA" and lists three patents dated Aug 16, 04, Sep 13, 04 and Jan 26, 15. It's relatively heavy just under 4 pounds (1.8 kilos). This particular phone has sentimental value because I found it in my grandfather's basement after he died. My grandfather ran a radio/TV repair shop in Boston from the 1920's to the early 1970's.Sam's Radio Stores Label.
Additional Reading:
I was Director of R&D at Ithaca InterSystems starting in late 1979. We built/marketed the fastest CP/M system ever sold; we were the first to build/deploy a DMA disk controller (all previous controllers were accumulator transfer), interrupt driven I/O, extended mapped memory (to get around the Z-80 64K address space) which we used for track-at-a-time disk reads and caching. For some long running applications, we took processing time from over 48 hours to less than one hour.
I was the author of the Pascal/Z compiler and later a multipass optimizing compiler for the IBM PC (SBB Pascal); for more info see page 42.
Please send questions/comments/suggestions (or more vintage hardware ;-) ) to jeff@rtr.com.
I'm always interested in finding more vintage computer memorabilia.
Please let me know if you know of any.
I'm particularly interested in old DEC PDP 8 and PDP 11, IBM 370, HP 1000, DG
Eclipse, IMSAI 8080 and Ithaca InterSystems DPS-1 related items as they all have
some sentimental value, but anything that is old and computer related would be
awsome :-)