The Commodore 4040 is the replacement for the previous models 2040 (U.S.) and 3040 (Europe). It's a dual-drive 5¼" floppy disk subsystem for Commodore Business Machines. It uses a wide-case form, and uses the parallel IEEE-488 interface common to Commodore PET/CBM computers.
These drive models use a single-density, single-side floppy data storage format similar to that used by the Commodore 1540 & 1541 drives, but with a slightly different data marker indicating which model originally formatted the disk. The low-level disk format is similar enough to allow reading between models, but different enough that one series of drive models cannot reliably write to disks formatted with one of the other model series. A difference of one extra 'header' byte is what causes this write incompatibility.
The Group Coded Recording (GCR) scheme of binary encoding is used to store data on the magnetic disk medium. The drive also uses variable bit-clock to enable increased data density on a standard single-density floppy disk. It is a form of constant bit-density recording done by gradually increasing the clock rate (zone constant angular velocity, ZCAV) and storing more physical sectors on the outer tracks than on the inner ones (zone bit recording, ZBR). Starting with the Commodore 2040 drive, this enabled Commodore to fit 170 KB on a standard single-sided single-density 5.25" floppy.
ReferencesEdit
^ abcd"Early IEEE Disk Drives". Retrieved 2020-04-18.
^"2040 SERIES SERVICE MANUAL" (PDF). Retrieved 2020-04-22.
commodore, 4040, this, article, multiple, issues, please, help, improve, discuss, these, issues, talk, page, learn, when, remove, these, template, messages, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding. This article has multiple issues Please help improve it or discuss these issues on the talk page Learn how and when to remove these template messages This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Commodore 4040 news newspapers books scholar JSTOR April 2023 Learn how and when to remove this template message This article possibly contains original research Please improve it by verifying the claims made and adding inline citations Statements consisting only of original research should be removed April 2023 Learn how and when to remove this template message Learn how and when to remove this template message The Commodore 4040 is the replacement for the previous models 2040 U S and 3040 Europe It s a dual drive 5 floppy disk subsystem for Commodore Business Machines It uses a wide case form and uses the parallel IEEE 488 interface common to Commodore PET CBM computers Commodore 4040Front view of the Commodore 4040 dual disk drive ManufacturerCommodore Business Machines Inc TypeFloppy disk driveMedia2 5 double sided floppy disk SS SD 1 Operating systemCBM DOS 2 6 1 CPUMOS 6502 amp MOS 6504 1 MHzMemory4 KB SRAM 8 2114 10 KB ROM 1 6332 1 6316 2 Storage170 KB per disk 1 ConnectivityParallel IEEE 488 1 BackwardcompatibilityCommodore PET CBM 4000 series 8000 series B128PredecessorCommodore 2040 amp 3040SuccessorCommodore 8050 amp 8250RelatedCommodore 2031 amp 1541These drive models use a single density single side floppy data storage format similar to that used by the Commodore 1540 amp 1541 drives but with a slightly different data marker indicating which model originally formatted the disk The low level disk format is similar enough to allow reading between models but different enough that one series of drive models cannot reliably write to disks formatted with one of the other model series A difference of one extra header byte is what causes this write incompatibility The Group Coded Recording GCR scheme of binary encoding is used to store data on the magnetic disk medium The drive also uses variable bit clock to enable increased data density on a standard single density floppy disk It is a form of constant bit density recording done by gradually increasing the clock rate zone constant angular velocity ZCAV and storing more physical sectors on the outer tracks than on the inner ones zone bit recording ZBR Starting with the Commodore 2040 drive this enabled Commodore to fit 170 KB on a standard single sided single density 5 25 floppy References Edit a b c d Early IEEE Disk Drives Retrieved 2020 04 18 2040 SERIES SERVICE MANUAL PDF Retrieved 2020 04 22 Commodore Knowledge Base This microcomputer or microprocessor related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Commodore 4040 amp oldid 1152005078, wikipedia, wiki, book, books, library,
