Dan Tobias at 17:49, 18 March 2013

2013-03-18T17:49:07Z

Dan Tobias: Created page with "{{FormatInfo |formattype=physical |subcat=Magnetic tape |subcat2=Audio Cassette }} '''Atari data cassettes''' store programs or data for the Atari 400 or 800 computers. == F..."

2013-03-18T17:35:58Z

Created page with "{{FormatInfo |formattype=physical |subcat=Magnetic tape |subcat2=Audio Cassette }} '''Atari data cassettes''' store programs or data for the Atari 400 or 800 computers. == F..."

New page

{{FormatInfo
|formattype=physical
|subcat=Magnetic tape
|subcat2=Audio Cassette
}}

'''Atari data cassettes''' store programs or data for the Atari 400 or 800 computers.

== File structure ==

A file stored on cassette has this overall structure:

* 20-second leader (mark tone)
* A series of data record frames
* An end-of-file frame

== Data record frame ==

The data record frame has this structure:

* Pre-record write tone (PRWT)
* Data record body
* Post-record gap (PRG)

== Pre-record write tone ==

The pre-record write tone has two forms, depending on whether the write OPEN mode was "stop/start" or "continuous write".

For stop/start, the PRWT is 3 seconds of mark tone.

For continuous write, the PRWT is .25 second of mark tone.

== Post-record gap ==

The post-record gap also has two forms for the two write OPEN modes.

For stop/start, the PRG is up to 1 second of unknown tones.

For continuous write, the PRG is from 0 to n seconds of unknown tones, depending on program timing.

An inter-record gap (IRG) consists of the PRG of the first record followed by the PRWT of the next record.

== Data record body ==

The data record is a fixed-length record of 132 bytes, stored as as sequence of bits going from high bit to low bit. This is in the following order:

* Two speed measurement bytes: 0 1 0 1 0 1 0 1
* Control byte (FC indicates full data record, FA indicates partial data record [only found in last record of file], FE indicates an all-zero end-of-file record)
* 128 data bytes (last byte is set to number of data bytes in record for partial data records)
* Checksum

== Links ==
* [http://archive.org/details/bitsavers_atari40080mputerTechnicalReferenceNotes1982_20170986 Atari reference manual] (lots of tech details)

← Older revision		Revision as of 17:49, 18 March 2013
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	== Links ==		== Links ==
	* [http://archive.org/details/bitsavers_atari40080mputerTechnicalReferenceNotes1982_20170986 Atari reference manual] (lots of tech details)		* [http://archive.org/details/bitsavers_atari40080mputerTechnicalReferenceNotes1982_20170986 Atari reference manual] (lots of tech details)
		+
		+	[[Category:Atari computers]]

Atari data cassette - Revision history

Dan Tobias at 17:49, 18 March 2013

Dan Tobias: Created page with "{{FormatInfo |formattype=physical |subcat=Magnetic tape |subcat2=Audio Cassette }} '''Atari data cassettes''' store programs or data for the Atari 400 or 800 computers. == F..."