Commodore Datasette

[christo930]

Does anyone know why Commodore went with a standard cassette recorder mechanism in the Datasette? Since you had to use the Datasette to use compact cassettes to store data, they could have improved the reliability and speed by running the tape faster (like maybe 3.75ips or twice as fast) or by using only 1 'side' of the cassette, but combined all four tracks as a single track.

 

Running the tape twice as fast would have limited the storage, but the Datasette was designed for the PET which means they weren't ever going to have problems with standard 60 minute cassettes and the use of the area of the tape including the space between tracks meant they could have made up for the faster speed with better density.

 

As far as I know, the only other tape based computer that did something similar, though far more radical, was the Adam.which used slightly modified type I cassettes at 20 inches per second. If you happen to know if there are any other tape based systems that used compact cassettes in a different way, i'd appreciate a name or link.

 

My guess is that they just didn't want to spend the money, but then they didn't need to design the datasette (and risk losses by it not selling) and just put a tape jack on it. The only real benefit of the Datasette is level control and the Datasette's ability to tell the computer the play or record buttons were pressed. The bottleneck doesn't appear to be a DAC as there were plenty of fastloaders for it, some of which were pretty fast.

[Chris++]

There's probably some insight here, although it will take a bit of thread-searching; it wouldn't hurt to re-ask the question in the "General" forum.

 

http://www.lemon64.com/forum

 

 

Edited April 22, 2015 by Chris++

[Oge]

Because, to my opinion:

1) It would have caused troubles with the production/mastering of cassettes;

2) The more the specification was distant from the standard, the more the Datassette would have costed;

3) Faster speeds would have meant the need for an improved circuitry/filtering and mechanics..

Cheers,

Oge

[Rybags]

Using the entire tape would mean a non-standard head would be needed, at that time probably a big cost increase.

As it was, they use a mono head which was probably a bit cheaper than a stereo one.

Running the tape quicker would likely mean different internal mech or at least motor, again a big cost increase.

 

It's likely they got the entire tape mechanism for 20 bucks or less and remainder of cost was electronic innards for digital interface and the case.

Name of the game for C= was to undercut everybody so it made sense to keep the tape drive simple.

 

And as it was, they crammed bit-banging functionality all over the place - just look at the C64s assignments among the 2 CIAs (and shared stuff with keyboard at that) and the 6 bits that the 6510 had available. Having 4 bit I/O would probably have meant either deleting something else or adding extra IO capability to the host machine.

Edited May 20, 2015 by Rybags

[Oge]

The Datassette was so prone to external interferences that several magazines advised to put an allumium foil on its base to improve reliability when loading or saving files.

 

Furthermore, it had an additional ground cord that a lot of people cut away though it truly improved reliability if connected to ground (e.g. a metal chassis).

 

I suppose that this was not needed if the Datassette was built with a larger budget so no wonder that their purpose was far away from pushing the cassette technology to its limit.

 

 

Cheers,

Oge

Edited May 23, 2015 by Oge

[7800fan]

The Datassette was so prone to external interferences that several magazines advised to put an allumium foil on its base to improve reliability when loading or saving files.

 

Furthermore, it had an additional ground cord that a lot of people cut away though it truly improved reliability if connected to ground (e.g. a metal chassis).

 

I suppose that this was not needed if the Datassette was built with a larger budget so no wonder that their purpose was far away from pushing the cassette technology to its limit.

 

 

Cheers,

Oge

 

I'm sure many of those people never noticed the drive came with a super long 15' or so cord, it was so the user could put the drive far away from the CRT.

 

What about 8-tracks? It may have been near end of life in mid 80's but I'm sure CBM could have gotten 8 track drive cheap (by manufactures who overproduced supply and have a few millions to unload) and it'd hold a whole lot more data than regular cassette. Plus at that time used 8 track tapes were cheap in flea markets so people could probably get crappy songs and erase it to use it for Commodore computers.