Casey Bralla The NerdWorld Report

J. R. Casey Bralla
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NerdWorld Computer Museum

(Last updated October 23, 2024)

A collection of old, and not-so-old computers I've been playing working with.

Exhibits

TRS-80 Model 100TRS-80 Model 100
Osborne 1 Osborne 1
Eee PC Eee PC Netbook
PiDP-8 PiDP-8I (DEC PDP-8/I Simulator)
HP 95LXHP 95LX Palmtop Computer
IBM 340 / Windows 95IBM 340 / Windows 95
Sharp EL-5400Sharp EL-5400 Calculator / Pocket Computer
Sharp EL-5400Domestic Fuse Box Circa 1910
Sharp EL-5400Apple IIe







TRS-80 Model 100

TRS-80 Model 100

The TRS-80 Model 100 was one of the first portable computers. Debuting in 1983, I was lucky enough to see one in use in the wild (and lust after it) that year. My Model 100 was purchased from a garage sale circa 2010.

My model reports 29,382 bytes free when BASIC is started. I presume this means the entire machine has 24K RAM, meaning it sold for about $1,400 in 1983. Included in that price was a nifty leatherette carrying case, and a large spiral-bound manual.

The Model 100 is powered by 4) AA batteries, or a wall-wart power supply. Programs are saved on cassette tapes, as was common during that era. There is a switch on the back which allows you to keep power to the RAM when the unit is shut off. This strikes me as a good feature, considering how slow and unwieldy cassette storage was.

TRS-80 Model 100
Model 100 In Leatherette Case with Manual

TRS-80 Model 100
Model 100 Menu

TRS-80 Model 100
Model 100 Microsoft BASIC

TRS-80 Model 100
Model 100 Nameplate

TRS-80 Model 100
Model 100 Rear Panel

TRS-80 Model 100
Model 100 Tag

TRS-80 Model 100
Model 100 Battery Compartment and Memory Power switch

TRS-80 Model 100
Model 100 Option ROM slots



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Osborne 1

Osborne 1

The Osborne 1 was one of the first "luggable" modern PC. Running the ubiquitous CP/M operating system, it was a sensation in 1981. It packed dual floppies, a 5" CRT screen, and keyboard into a single portable package.

By today's standards, this thing is a beast. It is theoretically portable, but you can skip your workout in the gym whenever you have to carry it since it's so darn heavy. The screen is tiny, made worse by my aging eyes. Still, the tiny CRT is actually pretty good, albeit very small. The keyboard feels remarkably nice, being from the days when keys actually had some travel distance, and not the horrible chicklette style that I detest today.

Adam Osborne, its creator and namesake, was somewhat famous at the time, having previously written the book "An Introduction to Microcomputers" in 1976. (This was a book I devoured while in college.) Osborne is also famous for killing his own company by announcing the next generation of machines before they were ready, thereby convincing his customers to stop buying Osborne 1's and wait for the next model (which never arrived).

My Osborne 1 was bought on eBay in 2024, and seems to work perfectly.

Osborne 1
Osborne 1 closed for transport

Osborne 1
Osborne 1 Nameplate

Osborne 1
Osborne 1 Bootup Screen

Osborne 1
Osborne 1 CP/M Screen


Osborne 1 Bootup Process



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Eee PC

Eee PC

The Eee PC is probably the stupidest name anyone could ever give to a computer. I don't even know how to pronounce "Eee" (is it like the sound you make when you see a mouse?). [BTW, how do you pronounce "Asus"? Is it "Aye-SOOSE", "Aye-SUSS", or "ASSes"? I prefer the first, but I've got no data to back up my preference.]

The Eee was one of the original "netbooks".

Early Netbooks often had solid state flash drives. These were small, very stingy with power, and mechanically robust to provide good durability. More recently, netbooks tend to come with traditional hard drives. My Asus has a 250 GByte conventional hard drive.

Mine is a model 1015-PEM-PU. I purchased this as a christmas present in 2010.

This has the following specs:

I chose this model mostly because of the dual-core processor and the large hard drive. I had been very concerned that the atom processor just wouldn't have enough "umpf" to be useful, so elected to trade the 1.6 GHz single-core for the slightly more expensive 1.5 GHz dual core. I also chose the Asus over the Dell or Acer because there is a well-established group installing Debian on the Eee. Also, I've read some casual comments that the quality of Acer & Dells is somewhat inferior to the Asus. Not having truly used either competitor, I don't know if those comments were well founded or not.

The Eee was shipped with a stripped-down version of Windows 7. Since I am an anti-windows Linux nerd, I always planned to install Linux on the netbook. I first backed up the entire drive using the "dd" command, just in case Linux balked at installation. This turned out to be unnecessary, as Debian Linux installed without too much trouble. (See how it did it, please read Debian on an Eee PC Netbook) Later, I even installed the compile-from-source Linux distribution Gentoo on it.

The Eee is somewhat bulky, with its thick "clamshell" design. As of 2024, you can still purchase batteries for it. The power plug always felt like it was too small and likely to break, but mine has held up just fine. I used mine quite a bit for traveling, but the keyboard is somewhat cramped, and the screen size (1024x600) is too squat and feels cramped.

The Eee is old and very dated, but still somewhat useful. Currently, my Eee runs Debian 12 with an xfce4 desktop. I use it exclusively as a terminal for my PiDP8 replica minicomputer.

Eee PC
Eee PC closed

Eee PC
Eee PC in use as terminal for PiDP8



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PiDP-8I (DEC PDP-8/I Simulator)

PiDP8i

The Digital Equipment Corporation (DEC) PDP-8 was a "minicomputer" from the late 1960's through the late 1970's. My first encounter with an actual computer was a PDP-8, and I was mesmerized from the start. My high school bought one of these things circa 1973 for around $18,000, which was incredibly inexpensive for a computer in those days. The operator (me) used a slow, loud teletype for entering, editing, and running programs. There were no floppy disks or hard drives in those days. Programs could be stored on small reels of 3/4" magnetic tape that would magically spin forward or back to find and load programs. If I wanted to take a program home with me, I could also save it on paper tape. Bootstrapping was done by entering a specific octal address pattern on the front-panel toggle switches, then pressing "Run". Of course, only 1 person could use the machine at a time.

The PDP8 had a wonderful front panel with lots of blinkin' lights and toggle switches. The lights (not LEDs!) would display all kinds of information (which I never understood) showing the binary data in various CPU registers. A skilled technician could use those lights and switches to enter programs or diagnose problems.

The PiDP-8 here is a replica of the DEC PDP-8/I. (Real PDP-8's from the 1970's are still available, but they are huge, expensive, and power-hungry beasts.) My PDP-8 is a 60% sized replica of just the front panel of LEDs and switches which connects to a Raspberry Pi through its GPIO connector. Unfortunately (or fortunately, depending on your viewpoint), none of the refrigerator-sized parts are included; it's just the front panel.

The Pi is kind of like the Wizard of Oz, hiding behind the curtain and orchestrating the impressive light show. It runs a simulator of the PDP-8, with special software called SIMH. SIMH, which can also mimic dozens of other old computers, creates a virtual PDP-8 in software and runs the actual old software (OS/8) used on the PDP-8 in the 1970's. Since the Raspberry Pi is so much faster than a 1960s vintage computer, we actually have to throttle the Pi down to make it work at the typical speed of an old PDP-8.

As previously mentioned, the PDP-8 predated LEDs, so it used conventional tiny incandescent light bulbs instead. But my simulator uses modern LEDs. Incandescent bulbs don't perform like LEDs. Unlike LEDs, which turn on and off almost instantly, there is a slight delay while the filament comes up to temperature. Conversely, when shut off, the light fades as the filament slowly cools down. The SIMH program has a special subroutine which mimics the performance of an incandescent light bulb and more faithfully duplicates the look on the original PDP-8. (This is actually disappointing, because the flashing is not nearly as "crisp" as you would like. Luckily, you can disable this subroutine if you want. However I decided to maintain it for a more true-to-life incandescent look.)

Although I once owned an actual teletype (Ugh, I got rid of it 30+ years ago. I wish I still had it!!), I use my Asus Eee PC as a terminal and log in via ssh. I start the SIMH simulator with a shell script, and I quickly get an OS/8 dot prompt from the PiDP8.

I haven't spent too much time poking around inside the old DEC operating system . Mostly, I've just written a basic program to exercise the front panel a bit. Luckily, OS/8 was distributed with several games such as Conway's Life and various Star Trek games. I can still play those games on the PiDP-8.

PiDP8
PiDP8 with Eee PC Terminal

PiDP8
PiDP8 SimH and OS/8


PiDP8 in Use



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HP 95LX Palmtop Computer

HP 95LX and Manual

The HP 95LX was one of the best "Palmtop" computers. Introduced in spring 1991, it consisted of a tiny foldable computer with 512 KBytes of RAM. The size is about the same as a modern smart phone, only about twice as thick. The User's Guide was a thick paperback, significantly larger than the computer.

Built-in software included the then wildly-popular Lotus 123 spreadsheet, as well as a scheduler, phone book, and calculator. It used those wonderful HP calculator keys from the early 1970's. The keyboard was necessarily cramped, which precludes touch typing. But since it's such good quality, typing really isn't that bad.

The 95 came in 2 variants, the F1000A with 512 KBytes (which is the one I own), and the F1010A which had 1 MBytes. [Oddly, I've got the F1000A, but the front panels says it has 1 MByte or RAM. Huh??] Both versions sported a 40 character by 16 line un-illuminated LCD screen. The screen on my 95LX is suffering from "polarizer burn", which leaves a large oval dark spot in the center, making using the computer almost impossible. I plan to replace the screen in the future from Thaddeus Computing for a nominal fee (that is 3 times the price I paid for the computer [sigh]) The CPU is a NEC V20, a souped-up clone of the 8088. The operating system is Microsoft DOS 3.22.

For storage and communication, there were several options. Firstly was a PCMIA card for RAM that acted like a solid-state disk drive. A separate button battery on the card kept power to the RAM, even when the 95 was shut off. There is no internet stack, of course, but the 95LX could communicate through an RS-232 interface (custom physical port format, naturally), or via infrared LED to another 95LX.

The 95LX is powered by 2 AA batteries. There's also a button battery on board, which I presume keeps the power applied when the AA batteries are replaced. A small wall-wort power supply can also be used to save the batteries.

PiDP8
HP 95LX and Memory Card

PiDP8
HP 95LX Closed

PiDP8
HP 95LX Lotus 123 Built-in

PiDP8
HP 95LX File Manager

PiDP8
HP 95LX Memory Card with Battery

PiDP8
HP 95LX Burned Polarizer



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IBM 340 / Windows 95

IBM 340 / Windows 95

The IBM 340 was a computer produced in the midst of a hardware industry transition in 1996. Equipped with a Pentium III processor at 166 MHz, it sported both a classic 16-bit ISA bus and several of those new-fangled PCI slots in a trim desktop format. Launched after the successful introduction of Windows 95, it has a prominent "Designed for Windows 95" sticker on the case. Rounding out the then-recent technology, it sports an IDE disk interface and VGA output. Interestingly, this system predates the ATX power supply. Notice the "Safe to Shut Down" message and the physical push-to-toggle power button on the front of the case.

My 340 has an updated IDE hard drive and an old Dell flat screen VGA monitor. I've also added a PCI ethernet card and done a fresh install of Windows 95. This 340 has a hefty 16 MBytes of RAM, with two 72-pin memory slots still available for more. There are no USB ports on this antique machine, so the keyboard and mouse both require PS/2-style connectors.

Getting modern TCP/IP networking working on this old guy still presents some challenges that I have not yet conquered. Drivers for my PCI network card are theoretically available, but I have been unsuccessful installing them as of this date. Windows 95 was designed for the Netware and Windows peer-to-peer networking world. The Internet existed then, of course, and Windows 95 claimed full Internet capability with it's splash screen that prominently advertises Internet Explorer. But in those days, most people logged in via a modem and ethernet was just for the office. A TCP/IP stack is included in Win95, but not installed by default. Even after installing TCP/IP, I still need to bludgeon the system some more before I can get Internet Explorer to work.

IBM 340
IBM 340 Boot Screen

IBM 340
IBM 340 Name Plate

IBM 340
Front panel

IBM 340
Windows 95 System Info

IBM 340
Manual Power Control



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Sharp EL-5400 Calculator / Pocket Computer

Sharp EL-5400

The Sharp EL-5400 was an early hybrid between a scientific calculator and a pocket computer. Introduced in 1984, it offers a full suite of scientific and statistical calculator functions, but also includes BASIC in ROM. There is an interface connector on one edge so the computer could be connected to a printer for output, or an available tape interface for saving programs.

I acquired mine some time in the late 1980's. (I don't remember how or when.) I remember that a colleague at work used to borrow it so his wife, who was a teacher, could use it to calculate grades for her students.

The unit is small enough to fit into a large pocket, or easily into a briefcase. There is a plastic cover that slides over the top, protecting the face from damage. The inside of this cover has a cheat sheet of functions and error messages.

Power comes from a pair of standard CR-2032 button batteries. At one point, I thought my unit had died since it wouldn't turn on after pulling it out of storage and replacing the dead batteries. Luckily, pressing the hardware reset button on the back brought it back to life. Not bad for a computer that is 40 years old!

Sharp EL-5400
BASIC Programming

Sharp EL-5400
Closed up for travel or storage

Sharp EL-5400
Cheat Sheet inside the cover



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Domestic Fuse Box Circa 1910

Fuse Box Circa 1910

Ok, This isn't a computer, but Wow! This is a fantastic example of domestic electrical technology, circa 1910.

In the late 1970's and early 1980's, I lived in a 4-unit apartment in Cleveland, Ohio. The 2-story apartment building had been constructed some time around 1910. In the early 1980's they must have discovered how gawd-awful dangerous the electrical system was in the building, because the old fuse box was removed and replaced by modern circuit breakers. (They did NOT rewire the whole building, however.) I pulled this out of the trash during the renovation, thinking it was pretty darn cool.

Incredibly, the "fuse" was actually just a bare lead wire held between two knurled thumbnuts. In the event of an electrical overload, the lead wire would heat up and eventually melt, thereby breaking the electrical circuit. Just think of how slowly and unreliably the fuse would activate in an overload situation. This was an apartment fire just waiting to happen!

You can clearly see the 3 bus bars which bring in 3-phase 220 Volts, with multiple taps for 110 Volt services. The whole thing is mounted on a beautiful (and heavy!) piece of marble. It was built by the Cleveland Switch Board Company, which was a local Cuyahoga County company started in 1907 and merged out of existence in 1982. The lead wires are long gone, so I've replaced them with 18-gauge copper wire. [I shudder to think if someone had done that before this ugly beast was replaced. I wonder how hot those wires would have to get before they melted and cut off the overload.]

Fuse Box Circa 1910
Lead Wire Fuses (Replaced by copper wire for this photo)

Fuse Box circa 1910
Made locally in Cuyahoga County Ohio

Fuse Box Circa 1910
3-Phase, 220 Volt Input



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Apple IIe

Apple IIe

The Apple IIe was the computer I wish I could have afforded back in the early 1980's. It was produced in 1983 and includes expansion cards for extra memory, 80-column video, serial, parallel, and dual floppy disk drives.

The Apple II was a very nicely designed system. It incorporated a built-in keyboard, a new-fangled switching power supply, and memory mapped expansion slots that were easily accessed through a removable top panel. The sturdy case provided a platform for floppy disks and a CRT monitor. The video output was composite video, making high resolution displays fuzzy and difficult to see. I use an old flat screen TV for the monitor, but even this provides shaky output when used in 80-column mode. I hate to think how 80 columns would have looked back in the day on a real CRT.

My Apple is pretty well equipped with memory, expansion cards, and dual floppies. Due to Steve Wozniak's clever engineering, each Single-Sided, Single-Density floppy holds a whopping 140 KBytes of data. One disk is typically used to boot the Operating System, while the other is for data.

There are several version of BASIC included, and the built in Monitor program in ROM is surprisingly robust. My system has 2 different DOSes; Apple DOS 3.3 and ProDOS. I've played around with each, but they both seem very similar to me. Wikipedia has more detail on their histories and differences

Apple IIe
Good keyboard for it's day

Apple IIe
Easy access to expansion cards

Apple IIe
Easy access Expansion cards

Apple IIe
Several expansion cards

Apple IIe
6502 Motherboard with ROMS

Apple IIe
Booting to DOS



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