Broken Capillaries Acaii

wonders of technology - as the hosts were still in their infancy ...

full report in pdf format: wonders The technology

The core memory

about 1980 were Data General computer of the type Nova or Eclipse with so-called core Save equipped. This DG machines were expensive and very maintenance intensive. From today's perspective, especially the RAM technology at that time was quite primitive, but on the other hand, considerable.

The core memory (32 Kbytes with 4 x 8kByte nuclear disks) of the computer crashes was investigated by default with the Checkerboard program on errors. In particular, on closer examination are the core memory boards (400 x 400 mm) wonders of technology. The core area of 8kByte core memory on the following image is 155 x 135 mm.

In the following photo of the bottom corner of this area you can look at the wiring of the cores a bit more accurate, but you need a Microscope the fine points to consider the near ... The ICs are part of the driver software and control the individual bits.

Magnification 10 x

Under the microscope (Traveler, 10 x) shows the single-cores, is more careful. Each core is crossed by several wires, so you can control each core individually. Each magnetic core represents a single bit.

magnification 60 x

Under the microscope (Traveler, 10 x) shows that you have coded the wires and alternating red and blue in color. These wires are single wires of copper and no traces.

magnification 200 x

single nuclei of 8kB memory under the Traveler USB microscope (200 x)

overheating of the driver electronics 8kB memory

the color of the printed circuit board in the driver area seems to overheating, which is visible on each disk, and obviously based on a design flaw.

Some tracks have a zigzag pattern Perhaps that should ensure a better conductivity ...

In the draft, the conductors are not digitized into a CAD design, but - as usual, ie the time before 1980 - are glued and then photographed ...

The core dump

The core memory had the advantage that the memory content was maintained when switching off. Therefore, it was often possible after switching off the computer or power failure simply start with a "Continue". Only after the memory test, the memory has been destroyed, and of course had to be ready to start the bootloader.

The memory preservation made it possible now for a crash dump a , who was called in English core dump because he was from the core memory ("Core") is diverted.

dump or dump described in the data processing, a copy or extract of a memory content. The dump can be displayed on the monitor, printer or file, and use binary, octal or hexadecimal. A dump is usually used to diagnose problems (crash dump) or to measure performance.

If it is the contents of the registers of a processor, it is called Registerdump, it is the contents of main memory, of memory dump.

excerpts from a database known as Datenbankdump . They serve as a backup or can be used to migrate.

Linux / Unix, after a crash today created one more " coredump" . Here, the memory of the crashed process is written to a file and can later be analyzed with a debugger. The name is derived from coredump core memory (core memory in English) from, the original form of the main memory in computer systems. This dumps the register and memory dump of a process known as post-mortem dumps, from Latin post mortem (German "after death"). Furthermore, there are Linux / Unix, a program called dump, which can be used file systems with high data throughput.

For Microsoft operating systems, the Windows system service, Dr. Watson generates a dump after a crash.

The bootstrap

The bootstrap or bootloader started the DOS operating system that can be considered a precursor of the first DOS versions, or a test program, for example, the memory test that had to be loaded from tape. I wrote my own programs in Algol, the compiler of the standard software The Nova was one. Programs you write on a console, for example, on a Teletype console that looked like a Teletype.

Nova with a 16-bit design in 1969, a teletype console, 32 kB and 25 MB of core memory Diskspecicher started with toggle switches, which formed a so-called bootstrap. At the time, knew each operator of such a computer's boot loader by heart:

• 000 376 examine
• 060 120 deposit (only for the DOS boot on the system disk, for the start of a program of magnetic tape was a different code eg 060 122 mE provided)
• 000 377 next deposit examine
• 000 376
• start

In Datamation 7 / 83 documented Bern Leeds in the funny script " Real Programmers shun Pascal "that the typical programmer the system bootstrap bit by bit and know by heart that one button. Yes, that was still with us ... 1980-1984

To view the addresses and registers light bulbs were used, which blew over again, until one day in their place ado red LEDs in the Nova-machine installations.

From 1974, the Eclipse core with 32 kB memory and 80 MB of disk already advanced and had a pre-programmed boot loader, which could be launched with a toggle switch. In Wikipedia is a list of bootloaders lacking but in which the loader of the Nova and Eclipse.

The term bootstrap refers originally to the loop that is located at the back of a boot to facilitate the tightening of the boot. (To run a program on a computer where no operating system is running) The process of booting reminiscent in part to the Strive to do is pull on the boots own loop out of the morass.

Yes, it was a miracle that such a system could ever be brought to life.