retrocomputing

372 Articles

Core Memory Upgrade For Arduino

April 28, 2018 by 47 Comments

Linux programs, when they misbehave, produce core dumps. The reason they have that name is that magnetic core memory was the primary storage for computers back in the old days and many of us still refer to a computer’s main memory as “core.” If you ever wanted to have a computer with real core memory you can get a board that plugs into an Arduino and provides it with a 32-bit core storage. Of course, the Arduino can’t directly run programs out of the memory and as designer [Jussi Kilpeläinen] mentions, it is “hilariously impractical.” The board has been around a little while, but a recent video shined a spotlight on this retro design.

Impractical or not, there’s something charming about having real magnetic core memory on a modern CPU. The core plane isn’t as dense as the old commercial offerings that could fit 32 kilobits (not bytes) into only a cubic foot. We’ll leave the math about how much your 8-gigabyte laptop would have to grow to use core memory to you.

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The Forgotten Workstation: Sun JavaStation

April 10, 2018 by 56 Comments

These days, conversations about Java tend to center around Oracle and Google fighting it out in court. But back in 1996, Sun was the keeper of Java and promoted it heavily. They even released a diskless workstation that only runs Java applets. The Sun JavaStation was affectionately called the “Mr. Coffee” and [Cameron Gray] wants to show you how it worked and what’s inside of it.

A single screw frees the innards from the small case. Inside looks like a dense PC from the era, although the parts inside are a far cry from a typical PC. The CPU was a 110 MHz microSPARC II soldered directly to the motherboard. The four RAM slots could take up to 64 megabytes of PC RAM.

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A Retrocomputer Disk On A Chip

March 30, 2018 by 28 Comments

There have been a lot of different mass storage methods over the relatively short lifespan of the computer. Magnetic tapes, drums, all sorts of disks, and flash memory have each had their time. Each of these new innovations required some time to become easy to use. One of the early attempts to simplify using flash memory was the M-Systems DiskOnChip device. Looking like a standard 8K JEDEC-compatible memory device, it actually provided access to a flash disk drive ranging from 16MB to 1GB. [Smbakeryt] bought some of these devices and built an ISA board to provide a disk and clock for the old 8-bit bus. You can see a video discussion about the device below.

SanDisk bought M-Systems and discontinued the devices back in 2007. Of course, you can still design flash memory into your system, but the simple and efficient interface of the DiskOnChip is no more. It is a testament to how simple the interface is that the schematic for the little board fits on a page, including the DS12885 real time clock.

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Apple One, On FPGA

March 29, 2018 by 17 Comments

Today, Apple is known for iPhones, iPads, and a commitment to graphical user interfaces. But that wasn’t how it all started. The original Apple was a single board computer built around a 6502. In 1976, you could snag one for $666.66, but you needed to supply your own TV, power supply, and keyboard. [Alangarf] didn’t have an Apple 1, but he did have a 6502 CPU core for FPGAs from [Andrew Holme] that he fleshed out to an Apple I clone with a VGA output and PS/2 keyboard port. The project works with either an iCE40 board or a Terasic DE0 board. You could probably port it to other similar FPGAs.

This is much more practical than trying to find an original, as Apple bought a lot of the old boards back and destroyed them. According to the Apple-1 Registry there are only about 71 of the boards still in existence, and that’s with the annotation that 4 of those may be lost and 8 might be duplicates. We’ve heard that of those there are only six that actually still work.

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Forth Version 1 Runs Again

March 27, 2018 by 23 Comments

Some people love Forth and some people hate it. However, you usually think of Forth as something running on a little computer such as an 8-bit microcomputer. When [Chuck Moore] developed the system back in the 1960s though, it ran on an IBM 1130. [Carl Claunch] took a scanned listing of the original code and got it running once again.

There are actually a few blog posts with details. Luckily, Forth is pretty simple — especially the core parts. However, there are a lot of differences from a modern Forth. The most obvious is that the dot keyword starts a definition and does not print the top of stack. However, internal details are different too — the system, for example, stores characters in packed EBCDIC — an ASCII-like code used by IBM computers.

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Retrocomputing For The Forgotten

February 21, 2018 by 60 Comments

The world runs on marketing hype. Remember the public relations swirl around the Segway? Before it rolled out we were led to believe it was going to be remembered as fire, the wheel, and Segway. Didn’t really happen. Microsoft and IBM had done something similar with OS/2, which you may not even remember as the once heir-apparent to MS-DOS. OS/2 was to be the operating system that would cure all the problems with MS-DOS just as IBM’s new Microchannel Architecture would cure all the problems surrounding the ISA bus (primarily that they couldn’t stop people from cloning it). What happened? OS/2 died a slow agonizing death after the Microsoft/IBM divorce. But for whatever reason [Ryan C. Gordon] decided to write a Linux emulation layer for OS/2 call 2ine (twine).

We like retrocomputing projects even if they aren’t very practical, and this one qualifies. The best analog for 2ine is it is Wine for OS/2, which probably has something to do with the choice of name. You might be ready to click away since you probably don’t have any OS/2 programs you want to run, but wait! The good news is that the post has a lot of technical detail about how Linux and OS/2 programs load and execute. For that reason alone, the post is well worth a read.

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IBM 1401 Runs FORTRAN II Once More

February 11, 2018 by 41 Comments

The IBM 1401 is undeniably a classic computer. One of IBM’s most “affordable” mainframes, it ruled the small business computing world of the 1960’s. Unfortunately, computers aren’t often thought of as treasured heirlooms, only a handful of these machines survive today. The computer history museum has two machines. One from Germany, and the other recovered from a basement in Connecticut back in 2008. [CuriousMarc] and the rest of the team at the museum have been working diligently to restore the 1401, and they’ve hit quite a milestone — They can now compile and run FORTRAN II code.

Getting the 1401 to run FORTRAN II itself is quite an accomplishment. The hardest part was dealing with the 729 vacuum column tape drives. The team spent years building a hardware emulator which takes the place of the real drives. The emulator is driven by an old PC running windows. Tape images are stored as files, which can be loaded, rewound, and run just like a real 729.

Emulators are great, but [Mark] and his team wanted this to run on the real hardware. They first had to re-create a FORTRAN compiler tape. They ran a tape copier program on the 1401, then loaded an image of the compiler on their emulator. The computer dutifully copied the image to a real tape drive.

The team also needed a punched card deck of FORTRAN source code to compile and run. The first example in the FORTRAN manual is a Hilbert Matrix program. The team could have used a keypunch machine to punch the cards for the program, but that is a painstaking and error-prone process. One mistake, and they would have to re-punch an entire card — much like using an old typewriter with no White-Out or correction ribbon. Instead, they typed the source into a PC, then converted the file to a tape image. A small program instructed the 1401 to punch the source code out on cards for them.

At the moment of truth, shown first in the video, the 1401 reads FORTRAN II from tape, pulls in the source code from punched cards, compiles, runs, and then prints the result on its line printer. All the original hardware singing along just like it did in 1959.

If you haven’t been to the Computer History Museum yet, check it out! It’s also the site of Vintage Computing Festival West.

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