View source for Commodore 1540

{{Infobox information appliance  <!-- https://en.wikipedia.org/wiki/Template:Infobox_information_appliance -->
| name         = Commodore 1540
| title        = 
| image        = Commodore VIC-20 (2189566849).jpg
| caption      = A VIC-20 with connected 1540 disk drive seen in the upper-right of the image.
| manufacturer = [[Commodore International|Commodore Business Machines, Inc.]]
| type         = Floppy disk drive
| releasedate  = {{Start date|1981||}}
| price        = 
| discontinued = 1983
| media        = 5¼" [[floppy disk]] [[Floppy disk format#Single Sided, Double Density|SS SD]]<ref name="z40">{{Cite web |access-date=2020-04-18 |date=  |title=Commodore VIC-1540 & VC-1540 |url=http://www.zimmers.net/cbmpics/d1540s.html |quote=Media: Single Sided, Single Density |archive-url=  |archive-date= |url-status=  }}</ref>
| os           = [[Commodore DOS|CBM DOS 2.6]]<ref name="z40" />
| power        = 100, 120, 220, or 240 V 50/60 Hz 25 W (30 W max)
| cpu          = [[MOS Technology 6502|MOS 6502]] @ {{nowrap|1 MHz}}<ref name="w40">{{Cite web |access-date=2020-04-18 |date=  |title=Commodore VIC-1540 - c64-wiki |url=https://www.c64-wiki.com/wiki/Commodore_VIC-1540}}</ref>
| memory       = 2 kB RAM, 16kB ROM<ref name="w40" />
| storage      = 170 kB<ref name="w40" />
| connectivity = [[Commodore bus|Commodore proprietary serial IEEE-488]] 0.4 kB/s<ref name="w40" />
| dimensions   = 
| weight       = 
| compatibility= [[VIC-20]]<ref name="w40" />
| predecessor  = 
| successor    = [[Commodore 1541]]
| related      = [[Commodore 1570]] & [[Commodore 1571]]
}}

The '''Commodore 1540''' (also known as the '''VIC-1540''') is the companion [[floppy disk]] drive for the [[VIC-20]] [[home computer]]. It was introduced in 1982.<ref name="pctime_1982">{{cite web|title=Chronology of Personal Computers (1982) |url=http://pctimeline.info/comp1982.htm |date=2013-05-18|accessdate=2013-06-18|publisher=pctimeline.info|quote=Commodore International releases the 1540 Single-Drive Floppy for the VIC-20. [804.17]}}</ref><ref name="ocs_vic20">{{cite web|title=Commodore VIC-20 computer |url=http://oldcomputers.net/vic20.html |date=2010-11-08|accessdate=2013-06-18|publisher=oldcomputers.net|quote=1982: Commodore releases the 1540 Single-Drive Floppy for the VIC-20.}}</ref> It uses single-sided 5¼" floppy disks, on which it stores roughly {{nowrap|170 [[kilobyte|kB]]}} of data utilizing Commodore's [[group coded recording|GCR]] data encoding scheme.

Because of the low price of both the VIC-20 and the 1540, this combination was the first computer with a disk drive to be offered on the US market for less than {{nowrap|$1000 USD,}} although the combination of the [[Commodore 64]] and [[Commodore 1541|1541]] would prove more enduring. The 1540 is an "intelligent peripheral" in that it has its own [[MOS Technology 6502]] CPU (just like its VIC-20 host) and the resident [[Commodore DOS]] on board in [[Read-only memory|ROM]] &ndash; contrary to almost all other home computer systems of the time, where the [[DOS]] was loaded from a boot floppy and was executed on the computer's CPU.

Due to a timing conflict with the C64's video chip, the C64 doesn't work properly with the 1540. The better-known 1541 is mechanically and nearly electronically identical to the 1540 but has a revised ROM that permits it to work with the C64 by slowing the drive down slightly. However, it is possible to revert the 1541 into 1540 mode with a [[Commodore BASIC]] software command (<code>OPEN 15,8,15, "UI-" : CLOSE 15</code>) to permit better speed when used with a VIC-20.

{{CSS image crop 
<!-- this template is used to remove the extra border in the original image-->
|Image = Commodore VIC-20 (2189566849).jpg
|bSize = 1200
|cWidth = 400
|cHeight = 200
|oTop = 0
|oLeft = 800
|Location = right
|Description = Front of the 1540 floppy disk drive.
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The 1540 is relatively rare. While cheaper than most other drives of the day, it was more expensive than the VIC-20 computer itself, and the disk media was also still relatively pricey. Also, the relatively small memory of the VIC meant that the faster program loading times of the drive did not gain more than a few seconds compared to [[Commodore Datasette|tape media]]. Thirdly, almost all commercial software for the VIC-20 was sold on cartridge or cassette tape media, giving low incentive to buy a floppy drive. The C64 followed close on the heels of the VIC-20, quickly discontinuing the 1540. Most 1540s still in existence were modified with a 1541 ROM so it would work with a C64. Unmodified 1540s are now considered collector's items.

The launch price in Germany was {{nowrap|1898 [[Deutsche Mark|DM]]}} (approximate {{nowrap|970 EUR).}} The American version is named {{nowrap|VIC 1540}} and the German version {{nowrap|VC 1540.}}

== References ==
<references/>

{{Commodore disk drives}}

[[Category:VIC-20]]
[[Category:CBM floppy disk drives]]


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