Editing Commodore 1571 (section)

{{Use dmy dates|date=April 2020}}
{{short description|Floppy disk drive}}

{{Infobox information appliance  <!-- https://en.wikipedia.org/wiki/Template:Infobox_information_appliance -->
| name         = Commodore 1571
| title        = 
| image        = VC1571.JPG
| caption      = Commodore 1571 floppy drive
| manufacturer = Commodore Business Machines, Inc.
| type         = Floppy drive
| releasedate  = {{Start date and age|1985||}}
| price <!--intro--> = {{US$|300}} (1985) {{Inflation|US|300|1985|fmt=eq|r=-2}}
| discontinued = {{end date and age|1993}}
| media        = 5¼" [[floppy disk]] [[Floppy disk format#Single Sided, Double Density|DS DD]] using [[Group coded recording|GCR]] or [[Modified Frequency Modulation|MFM]]<ref name=z71>{{cite web | last1 = Zimmerman | first1 = Bo | title = Commodore 1570/1571 | date = 2015-03-20 | access-date = 2023-09-11 | url = https://zimmers.net/cbmpics/d1571s.html | website = zimmers.net | url-status = live | archive-url = https://web.archive.org/web/20230909031450/https://zimmers.net/cbmpics/d1571s.html | archive-date = 2023-09-09 | df = dmy-all }}</ref>
| os           = [[Commodore DOS|CBM DOS 3.0]]<ref name=z71/> {{nowrap|([[Commodore 128#Commodore 128D|128D]] uses v3.1)}}
| power        = <!--220 V 50 Hz ? W-->
| cpu          = [[MOS Technology 6502|MOS 6502]]<ref name=om-e>{{Cite web|title=Commodore 1571 disk drive user's guide |access-date=1 February 2024 |publication-date=August 1985 |publisher=Commodore Business Machines, Inc. |url=https://archive.org/details/1571UsersGuide/page/n121/mode/2up}}</ref> @ {{nowrap|2 MHz}}<!--clock from de.wikipedia -->, [[Western Digital FD1771|WD1770]]<ref name=zm71p03>{{Cite FTP |title=Memory map |access-date=27 April 2016 |publication-date=October 1986 |server=Commodore Business Machines, Inc. |url=ftp://www.zimmers.net/pub/cbm/schematics/drives/new/1571/manual/03.html}}</ref>
| memory       = 2 kB RAM 32 kB ROM<ref name=om-e/>
| storage      = 350-410 kB (GCR and MFM)<ref name=om-e/>
| connectivity = [[Commodore bus|Commodore proprietary serial IEEE-488]]<!--"Two Serial Ports"--> {{nowrap|5200 bytes/s<ref name=om-e/>}}
| dimensions   = 
| weight       = 
| compatibility= {{nowrap|[[Commodore 64]],}} {{nowrap|[[Commodore 128]]}}
| predecessor  = [[Commodore 1570]]
| successor    = [[Commodore 1581]]
| related      = 
}}

The '''Commodore 1571''' is [[Commodore International|Commodore's]] high-end 5¼" [[floppy disk]] drive, announced in the summer of 1985. With its [[Double-sided disk|double-sided]] drive mechanism, it has the ability to use double-sided, double-density (DS/DD) floppy disks, storing a total of 360&nbsp;kB per floppy. It also implemented a "burst mode" that improved transfer speeds, helping address the very slow performance of previous Commodore drives.

Earlier Commodore drives used a custom [[group coded recording]] format that stored 170&nbsp;kB per side of a disk. This made it fairly competitive in terms of storage, but limited it to only reading and writing disks from other Commodore machines. The 1571 was designed to partner with the new [[Commodore 128]] (C128), which introduced support for [[CP/M]]. Adding double-density [[MFM encoding]] allowed the drive to read and write contemporary CP/M disks (and many others).

In contrast to its single-sided predecessors, the [[Commodore 1541|1541]] and the briefly-available [[Commodore 1570|1570]], the 1571 can use both sides of the disk at the same time. Previously, users could only use the second side by manually [[Flippy disk|flipping them over]]. Because flipping the disk also reverses the direction of rotation, the two methods are not interchangeable; disks which had their back side created in a 1541 by flipping them over would have to be flipped in the 1571 too, and the back side of disks written in a 1571 using the native support for two-sided operation could not be read in a 1541.