Turbo Tape

Turbo Tape is the name of the most famous Cassette Quick loader. Subcassettes quick loaders refers to a series of programs for Commodore home computer, especially for the C -64, the accelerated loading and saving of programs on compact cassettes. Often all of these programs were unofficially referred to as Turbo Tape.

Technology

The in Kernal (operating system ) of the Commodore home computer implemented recording format for Datasette still came from the PET 2001 with its much smaller memory and was thus not optimized for speed, but at high data security. At the same time the development of minimally redundant error-correcting codes was in its formative years of the PET 1976 /77 still in its infancy. So simple all data blocks have been written twice and verified loading to compensate for drop-outs of the tape can. Furthermore, very large mark lengths were used for data recording used, each bit written with two markers ( short-long or long-short ), each byte provided with a parity bit, and bytes dropped by another marker apart to safely recognize this when reading to can. Even extra long opening credits were used to compensate for very long indescribable band parts at the beginning of the cassettes. Through these properties, the effective bit rate of the payload was limited to about 300 bits per second. When PET 2001, the maximum charging time of a memory- filled program (about 3 KiB ) was still under two minutes, but the C64 were obtained for one-piece, memory -length programs (50 KiB) load times of over 20 minutes, multipart programs could still longer overall load times require.

With better band material that was available at low cost in the course of the 1980s, it was possible to dispense with the duplicate record to record each bit only with a marker ( short or long), instead of the parity bit to use a single checksum bytes no longer delineate, and the mark length and the opening credits to greatly shorten without provoking too great a probability of default of the bands. This allowed for a given length of tape about ten times the amount of user data to be accommodated, the maximum charging time for one-piece programs were now well below 3 minutes. Thus, the different accelerator programs implemented their own, optimized for high density data tape formats. On compatibility of these formats among each other and with the original format was not respected, was instead mostly the matching Quick loader - to save space and time, only the portion required to read the data - in the original Commodore recording format directly in front of the then stored in a compressed format actual program played on the tape.

Since the Datasette unlike the Commodore floppy drives not transfer data from the drive to the computer, but the recording format of the data is the speed limiting factor, the cartridges fast charger only work if the data previously recorded with the appropriate quick memory program were. Bands in the standard format can thus not load faster.

The denser recording on the tape was also still combined by later quick-charge programs with a packer, resulting in a reduction of stored data volume and thus, further shortening the charging time revealed.

The " sound " of the stored sounds very different from the default storage (see audio sample under Datasette ). The sound frequencies had higher principle. For experienced users, it was therefore not a problem to determine, by listening to a data cartridge in an ordinary audio cassette recorder, and whether these were recorded in the standard Commodore format or with a quick charger.

Dissemination

Almost all games sold commercially on cassette used from approx 1983/84 own quick charger, almost always in conjunction with a short lead in the standard Commodore format, which then automatically reloading the rest of the program in its own format. Most commercial fast charger not shortened the mark lengths quite as strong as the original Turbo Tape to be producing less warranty claims by unreadable tapes. It has often been directly integrated into the rapid charger also the copy of these tapes realized by data encrypted, changes in the order, or have been recorded mixed with useless filler data.

Well-known " quick charger "

  • Turbo Tape 64
  • V4 Turbo Tape
  • Turbo Tape 61K
  • FlashLoad
  • Super Tape D2
  • Multitape I
  • Hypratape 64
  • In the Final Cartridge 2 and in the Final Cartridge 3 cassettes quick charge were also ( and fast memory ) contain functions.
Commodore International Commodore 64 Commodore Datasette Dropout (communications) Commodore 16 Listing (computer) The Final Cartridge III
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