The coolest thing about the SID chip (it was also in the VIC20), at least to me, was that it had a white noise generator. And you could read the wave level of the white noise generator.

The interaction of the white noise generator with the timing of the reads probably made the system complex past uncertainty. This made it possible to generate true random numbers.

It's fun to think that, at least. Please don't burst my bubble.

Actually, the SID chip was only found in the following CBM models:

  • C-64
  • C-128
  • C-65 (had two for stereo sound)
  • the PET-II series, consisting of the B128, the B500 series, the C-600 series, the C-700/P500 series.

The SID chip is basically a three voice synthesizer on a chip. It's a weird mixture of digital and analogue circuitry which account for it's distinctive sound.

There were two models of the SID both with several revisions, out of which the 6581R4 is probably the finest sounding there is. (this is of course only my personal opinion.)

The 12V 6581 was the first, and still the one which many consider the real SID. In the turn of the 90s, while the C64 went through a radical redesign (to the worse IMHO) CBM came out with the 9V 8580, that had most of the "bugs" fixed that were present in the 6581. That is the features that differed from the original spec. This might have been a godsend, if the nature of the chip didn't depend on these bugs!

Somewhere in between the 6581 and the 8580 was a chip called the 6582. Yes, it does exist. It's a 9V 6581 that you can drop into your C-128DCR or C-64II. These are pretty scarce and I've never seen one live myself.

The most important bug was, that when you changed the volume, the SID chip emitted a click. Some ingenious programmer found out, that you could emit different frequency clicks by different volume increments/decrements. You can guess what this meant? You could play back PCM samples on the SID, albeit very noisily, by making it click very fast.

The other bugs were voltage leaks and waveform bugs, but all this radically affected the smooth mellow sound of the 6581, transforming it to the more nasal, sharp tones that come out of the 8580.

If that wasn't enough, the filters were changed too, being 470pF capacitors on the 6581 and 22 000pF on the 8580. This also took something out of the magnificent analogue filters present in the chip.

The developer of the SID chip, Bob Yannes later went on to create Ensoniq, a well known synthesizer manufacturer.

All in all, the SID chip is a fine example of what results when an engineer is given literally free hands to design his chip. At the time, the SID was one of the best synthesizers made, and one could argue it still is.

You should check out the High Voltage SID collection at

Little updates, added some punctuation, added the 6582 and updated the machine list

The SID is the security Identifier in Windows NT and 2000. Each machine which is a part of a domain has a SID, as does each user account. Permissions are actually set for a SID, which is why you can change account names without hosing permissions.

sid is the name of the unstable development branch of Debian GNU/Linux, where most of the software packages are initially uploaded. It will never be released directly, because packages which are to be released first must be included in the testing branch in order to be released in the stable distribution. sid contains packages for both released and unreleased architectures. As in the other branches stable and testing, unstable consists of packages categorized into separate main, contrib, and non-free sections.

As with other Debian codenames, the name "sid" comes from the motion picture "Toy Story": Sid was the boy next door who destroyed toys. Sid is also considered by many to stand for "Still In Development", a possible backronym.

Originally, sid was the separate directory in which binary packages for unreleased architectures were placed. This layout became confusing and problematic when those unreleased architectures were then released, so it was changed to the current setup.

The advantage of using the unstable distribution is that it contains the latest bleeding edge software for Debian. However, this software is very untested so the unstable distribution can be buggy and otherwise problematic.

Compare: stable, frozen, testing, unstable; buzz, rex, bo, hamm, slink, potato, woody, sarge

Some famous SID composers:

You can still enjoy tunes by these composers and many others by downloading the HVSC, a collection of more than 20,000 SIDs (2003). You'll need a player (SID emulator) like sidplay2/w which can be found on

The legacy also lives on in terms of C64 remakes; amateur composers (often talented ones) who contribute with their own interpretations of SID classics. is a good place to start. I recommend the following artists:

Of course, this can't go without mentioning Press Play On Tape; a rock band playing C64 music on real instruments.

A few commercial bands even include actual SID sound in their work:

They don't actually use a C64 since the audio signal was originally combined with the TV video signal (See also: noise and hum). Instead they have hardware like SidStation or HardSID; both combine modern audio hardware with one or more SID chip(s). Ain't that something? It's like putting an ancient Rolls-Royce engine in a Hyundai.

On a last note for amateur composers: The audio software company reFX ( used sidplay2 technology to make a virtual C64 synth (a VSTi) called QuadraSID. Also, the music application Goat Tracker features a retro interface, and emulated SID sound.

The SID is also the System Identification for various Cellular network areas. For instance, the Washington DC area is 00013. Connecticut is 00088.

The SID is generally only a programmable feature on CDMA and TDMA phones, which can be manually programmed, and may need the SID to be reprogrammed to either prevent or allow roaming by the cell phone.

Much of the trouble experienced by customer support and Tech support comes of dealers trying to be clever about solving customer problems by reprogramming the SID.

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