Fast loader
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A fast loader is a software program for a
Floppy disks
Fast loaders came about because of a discrepancy between the actual speed at which floppy drives could transfer data and the speed that was provided by the operating system's default routines. This discrepancy was most pronounced on the VIC-20 and Commodore 64. While the earlier Commodore PET series had used an industry-standard IEEE-488 parallel bus, this was replaced with a custom Commodore serial bus on the VIC-20. The serial bus was intended to be nearly as fast as its predecessor, due to the use of the 6522 VIA as a hardware shift register on both the drive and computer. However, hardware bugs were discovered in the 6522 that prevented this function from working consistently. As a result, the KERNAL ROM routines were hastily rewritten to transfer a single bit at a time, using a slow software handshaking protocol.[1]
Although the C64 replaced the 6522 VIA with two 6526 CIA chips, which did not suffer from this bug, the companion 1541 disk drive still had a 6522 VIA. Commodore chose not to redesign the 1541 hardware, also in order to retain backward compatibility with VIC-20 peripherals; this however came at the expense of speed. Because of the transfer protocol, the Commodore 1540 and 1541 disk drives soon gained a reputation for extreme slowness. Only at the introduction of the Commodore 128 computer and the Commodore 1571 disk drive was the original plan put into action and a hardware shift register was used, reducing the need for special fast loaders.
Soon after the C64's release, some astute programmers realized that Commodore's
$
LOAD
routine. Next, the fast loader would transfer the necessary code into the drive RAM and order its execution, then receive the file sent by the altered transfer code. Depending on the exact nature of the routines used, the loading speed could be improved by as much as a factor of five.
This technique was used for a few of the many fast-load systems made (such as JiffyDOS). Others were simply more efficient in I/O and file handling, offering marginal to good improvement. Other products added parallel hardware.
Various software companies released fast loaders for the C64, usually in
Many commercial programs for the C64, especially games, contained their own fast-loading routines on the distribution media. The user would load a small "stub" program from the disk with the standard slow routines, which would then install faster transfer routines in both the computer and the drive before proceeding to load the rest of the program at high speed. This way, the user benefited from the fast loader without having to buy or know about a dedicated fast-loader product.
Several popular Commodore magazines published type-in fast loading software. In April 1985, Compute! published TurboDisk, a fast loader that included C64 and VIC-20 versions. This program proved popular and was republished in the July 1985 issue of Compute!'s Gazette.[2][3][4][5]
It was printed yet again in August 1986, without the VIC-20 version, but with several accompanying utilities to relocate the program in memory and to create auto-booting software that took advantage of TurboDisk's speed. A Commodore 128 version was also included for those C128 users who still had 1541 disk drives.[6][7][8][9][10][11]
COMPUTE!'s Gazette also published several other utilities that speed up C64-to-1541 communications, including Turbo Copy (a 4-minute full-disk copier),[12][13] TurboSave (a utility that accelerated the speed of disk saves)[14] and Quick! (another fast loader).[15][16]
The type-in fast loader fashion continued in the age of the Internet. Krill's Loader (2009) and Spindle (2013) are two examples of C64-to-1541 "IRQ loaders", fast loaders that allow programs (mainly games) to keep their own
Cassette tapes
The built-in routines for storing and reading data to and from
Such programs existed for several computers, such as the
Speedlock was a software protection system used on the
Some companies created software to bypass protection schemes, including Speedlock, for the purpose of
Invade-a-Load was a fast loader for cassette-based games which not only accelerated the loading of blocks from the tape, but also contained a
In the UK, where the price of a 1541 disk drive was beyond the means of many of the target audience of C64 owners, there was enormous demand for fast loaders for C64 games. One of the first to use such a loader was
Optical discs
In 1995, Yoichi Hayashi of Namco Ltd. invented a variant of the Invade-a-Load technique for use with optical disc based platforms such as PlayStation and applied for a patent. U.S. patent 5,718,632 was granted in February 1998 and assigned to Namco despite the Invade-a-Load prior art. The technique was used for Ridge Racer.
See also
- Commodore 64 disk / tape emulation
References
- ^ Brain, Jim (1996-01-10). "Vic-20/C-64 serial ports - alt.folklore.computers | Google Groups". Retrieved 2012-09-26.
- ^ Lewis, Don (July 1985). "TurboDisk". COMPUTE!'s Gazette. p. 34. Retrieved 2013-01-16.
- ^ Lewis, Don (July 1985). "TurboDisk". COMPUTE!'s Gazette. p. 36. Retrieved 2013-01-16.
- ^ Lewis, Don (July 1985). "TurboDisk". COMPUTE!'s Gazette. p. 37. Retrieved 2013-01-16.
- ^ "Bug-swatter". Compute's Gazette. January 1986. p. 120.
- ^ Lewis, Don (August 1986). "TurboDisk 64". COMPUTE!'s Gazette. p. 64. Retrieved 2013-01-16.
- ^ Lewis, Don (August 1986). "TurboDisk 64". COMPUTE!'s Gazette. p. 65. Retrieved 2013-01-16.
- ^ Lewis, Don (August 1986). "TurboDisk 128". COMPUTE!'s Gazette. p. 68. Retrieved 2013-01-16.
- ^ Lewis, Don (August 1986). "TurboDisk 128". COMPUTE!'s Gazette. p. 69. Retrieved 2013-01-16.
- ^ Bavaro, Dino (August 1986). "TurboDisk Relocator". COMPUTE!'s Gazette. p. 66. Retrieved 2013-01-16.
- ^ Rozenberg, Bert (August 1986). "Turbo BootMaker". COMPUTE!'s Gazette. p. 67. Retrieved 2013-01-16.
- ^ Cutrone, A.M. (April 1986). "Turbo Copy". COMPUTE!'s Gazette. p. 81. Retrieved 2013-01-16.
- ^ Cutrone, A.M. (April 1986). "Turbo Copy". COMPUTE!'s Gazette. p. 82. Retrieved 2013-01-16.
- ^ Voosen, William (April 1987). "TurboSave 64". COMPUTE!'s Gazette. p. 71. Retrieved 2013-01-16.
- ^ Zaky, Adib (December 1988). "Quick!". COMPUTE!'s Gazette. p. 82. Retrieved 2013-01-16.
- ^ Zaky, Adib (December 1988). "Quick!". COMPUTE!'s Gazette. p. 85. Retrieved 2013-01-16.
- ^ Williams, John (November 1983). "Fast Loading with Apple DOS 3.3". BYTE. pp. 502–504. Retrieved 2016-03-19.
- ^ Ellerbrock, R. (October 1986). "TurboDisk For DOS 3.3". Compute!. p. 83. Retrieved 2013-11-09.
- ^ Åkesson, Linus (2013-03-31). "GCR decoding on the fly". Archived from the original on 2017-03-21. Retrieved 2017-03-21.
- ^ Carlson, Edward H. (March–April 1980). "Fast Tape Read/Write Programs For Your OSI". Compute!. pp. 115–117. Retrieved 2013-10-25.
- ^ Strasma, James (March–April 1980). "The PET Rabbit". Compute!. p. 94. Retrieved 2013-10-25.
- ^ De Ceukelaire, Harrie (January 1985). "TurboTape / High-Speed Tape Utility For Commodore 64 And VIC-20". Compute!. p. 124. Retrieved 2013-10-30.
- ^ De Ceukelaire, Harrie (February 1985). "How TurboTape Works". Compute!. p. 112. Retrieved 2013-10-30.
- ^ "Capute!". Compute!. March 1985. p. 146. Retrieved 2013-10-30.
- ^ "Turbo 2000". AtariMax.
- ^ a b Eddy, Richard (1987). "The One David" (44). Crash. Retrieved 2013-01-09.
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(help) - ^ a b c Lerm Tape Utility D (instruction manual) (PDF). Lerm. 1990. Retrieved 2013-01-09.
- ^ North, Jon (1990). "How To Hack : Speedlock" (61pages=66–67). Your Sinclair. Retrieved 2023-07-28.
{{cite journal}}
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(help) - ^ Martin van der Heide, Martin Kopanske and Tomaz Kac (1997–1999). "Tape Decoding : Encoding schemes". World of Spectrum. Archived from the original on 2020-06-02. Retrieved 2013-01-09.
- ^ "CRASH review from 1985". Retrieved 2007-01-29.
- Newsfield Publications Ltd. March 1991. Retrieved 2019-06-17.