View source for Commodore SX-64

{{Short description|Portable version of the Commodore 64 computer}}
{{Use mdy dates|date=June 2019}}
{{More citations needed|date=April 2023}}
{{Infobox computer
| Photo        = [[File:Sx-64 build crop.jpg|320px|Hardware]]
| Type         = [[Portable computer]]
| Released     = {{Start date and age|1983|12}}
| Discontinued = 1986
| Processor    = [[MOS Technology 6510]] <br /> @ {{nowrap|1.02 MHz}} ([[National Television System Committee|NTSC]] version)<br /> @ {{nowrap|0.985 MHz}} ([[Phase Alternating Line|PAL]] version)
| Graphics     = [[MOS Technology VIC-II|VIC-II]] ({{nowrap|320 x 200}}, {{nowrap|16 colors}}, [[Sprite (computer graphics)|sprites]], {{nowrap|[[raster interrupt]]}})
| Sound        = [[MOS Technology SID|SID 6581]] ({{nowrap|3x [[Electronic oscillator|Osc]]}}, {{nowrap|4x [[Waveform|Wave]]}}, [[Electronic filter|Filter]], [[ADSR envelope|ADSR]], [[Ring modulation|Ring]])<!-- Tried to keep it short -->
| Connectivity = {{nowrap|2x [[MOS Technology 6526|CIA 6526]] [[Joystick]]}}, [[#I/O ports and power supply|Power]], [[ROM cartridge]] (modified), [[S-Video]], {{nowrap|[[Commodore bus|CBM-488]] [[Commodore 1541|Floppy]]/[[Commodore 64 peripherals#Printers|Printer]]}}, [[General Purpose Input/Output|GPIO]]/[[RS-232]]
| Memory       = {{nowrap|64 [[kilobyte|KB]] [[Random-access memory|RAM]]}} + {{nowrap|20 KB [[Read-only memory|ROM]]}}
| OS           = {{nowrap|Commodore [[KERNAL]]<br />[[Commodore BASIC]] 2.0}}
| price        = {{US$|995}} (1984) {{Inflation|US|995|1984|fmt=eq|r=-2}}
| predecessor  = {{nowrap|None}}
| successor    = {{nowrap|[[Commodore LCD]]}}
}}
[[Image:Commodore SX-64 standing.jpg|thumb|Housing with keyboard locked on, standing]]
[[Image:Commodore SX-64 connectors.jpg|thumb|Rear]]
[[Image:Commodore SX-64.jpg|thumb|Two Commodore SX-64 computers showing their SX-64 BASIC 2.0 startup screens. (Note the white screen background color.)]]
The '''Commodore SX-64''', also known as the '''Executive 64''', or VIP-64 in Europe, is a [[portable computer|portable]], briefcase/suitcase-size "luggable" version of the popular [[Commodore 64]] [[home computer]] and the first color [[portable computer]].<ref name="vintage-computer_commodoresx64">[http://www.vintage-computer.com/machines.php?commodoresx64 Commodore SX-64 Portable]</ref>

The SX-64 features a built-in five-inch composite monitor and a built-in [[Commodore 1541|1541]] [[floppy disk|floppy]] drive. It weighs {{nowrap|10.5 kg}} ({{nowrap|23 lb}}). The machine is carried by its sturdy handle, which doubles as an adjustable stand. It was announced in January 1983 and released eleven months later in December 1983, at $995 [[United States dollar|USD]] ({{Inflation|US|995|1984|fmt=eq}}).<ref name="oldcomputers_sx64">[http://oldcomputers.net/sx64.html Commodore SX-64 portable computer]</ref><ref name = "InfoWorld Feb 1984">{{Cite magazine | last = Mace | first = Scott | title = Commodore introduces new family of computers |magazine= InfoWorld | volume = 6 | issue = 6 | pages =11–12 | publisher = Popular Computing | location = Menlo Park, CA | date = February 6, 1984 | url = https://books.google.com/books?id=gC4EAAAAMBAJ&pg=PA11 | issn = 0199-6649
}} "[Don Richards, Commodore USA president,] also said that the SX-64 computer, a $995 portable version of the Commodore 64 with built-in color monitor, has been a sellout everywhere."</ref>

== Description ==
Aside from its built-in features and different form factor, there are several other differences between the SX-64 and the regular C64. The default screen color is changed to blue text on a white background for improved readability on the smaller screen. This can cause compatibility problems with programs that assume the C64's default blue background. <!-- (This is, however, often easily overcome by the user simply entering the appropriate [[BASIC]] [[PEEK and POKE|POKE]] commands to change screen colors and keystroke to change the cursor color to mimic the C64's default colors prior to loading of the program.)-->The default device for load and save operations is changed to the floppy drive.

The Datasette (cassette) port and [[RF modulator|RF]] port were omitted from the SX-64. Because it has a built-in disk drive and monitor, Commodore did not perceive a need for a [[tape drive]] or television connector. However, the lack of a Datasette port poses a problem for a number of C64 [[Centronics]] parallel printer interfaces, since several popular designs "borrowed" their +5V power supply from the port. This was not an issue for later interfaces which were supplied with an AC adapter power supply, or those which can use the +5V line supplied by the Centronics port (Pin #18) on the printer itself, if the printer implements it. Alternatively, a +5V supply is also available from the joystick ports.

The audio/video port is still present, so an external monitor can still be used;<ref name="benford198502">{{cite news|url=https://archive.org/stream/Ahoy_Issue_14_1985-02_Ion_International_US#page/n35/mode/2up|title=SX-64 Portable Computer|author=Benford, Tom|date=February 1, 1985|work=Ahoy!|access-date=October 15, 2013|pages=37–38}}</ref> it displays the same content as the built-in monitor.<ref name="cc19850121">{{cite episode | title=Ghostbusters demo | series=The Computer Chronicles | credits=Crane, David | network=PBS | url=https://www.youtube.com/watch?v=95L0gRRxs6k  |archive-url=https://ghostarchive.org/varchive/youtube/20211221/95L0gRRxs6k |archive-date=2021-12-21 |url-status=live| airdate=1985-01-21}}{{cbignore}}</ref> Differences, electrically and in placement on the board, means that there are compatibility problems with some C64 cartridges.

The original SX-64's (built in) power supply limits the machine's expandability.{{citation needed|date=October 2013}}

Compatibility with Commodore [[Commodore REU|RAM Expansion Unit]]s varies. Early SX-64 power supplies cannot handle the extra power consumption from the REU. The physical placement of the cartridge port can prevent the REU from seating properly. The 1700 and 1750, 128K and 512K units intended for the [[Commodore 128|C128]], are said to work more reliably with the SX-64 than the 1764 unit that was intended for the regular C64. Some SX-64 owners modify Commodore REUs to use an external power supply in order to get around the power supply issues.
IDE64 is also non-compatible at the present time. When it is powered up, the screen sends out the C64 breadbin "blue" background with the typical <code>38911 BASIC BYTES FREE</code>, and immediately under the <code>READY</code> prompt a statement of <code>RAM</code> is displayed.

A version of the SX-64 with dual floppy drives, known as the '''DX-64''', was announced, but the press reported by early 1985 that plans for its release had been suspended.{{r|benford198502}} A few have been reported to exist {{By whom|date=December 2017}}, but it is very rare. Instead of an extra floppy drive, a modem could also be built in above the first drive. Some hobbyists installed a second floppy drive themselves in the SX-64's empty drive slot.  Later models of the SX-64 use the larger power supply intended for use with the DX-64.

At around the same time the SX-64 was announced in January 1983, a version with a monochrome screen called the '''SX-100''' was announced. Despite releasing plans by June 1983, it was never released.

==History==
The SX-64 did not sell well, and its failure has been variously attributed to its small screen, excessive weight ({{cvt|10.5|kg|disp=or|1}}), poor marketing, and smaller business software library than that of its competitors, which included the [[Osborne 1]] and [[Kaypro II]] ([[Zilog Z80]] CPU, [[CP/M]] OS) and [[Compaq Portable]] ([[16-bit]] CPU, [[MS-DOS]]).

The exact number of SX-64 sold from 1984 to 1986, when it was discontinued, is unknown. The serial numbers of  over 130 SX-64s from series GA1, GA2, GA4, GA5 and GA6, with serial numbers ranging over 49,000 for series GA1, 1,000 for GA2, 17,000 for GA4, 11,000 for GA5, and 7,000 for GA6 have been reported<ref>[http://www.sx64.net/sn_database/sn_database.htm database] {{Webarchive|url=https://web.archive.org/web/20060615053711/http://www.sx64.net/sn_database/sn_database.htm |date=June 15, 2006 }} at SX64.net</ref>

Some would-be buyers waited instead for the announced DX-64, which never became widely available due to the slow sales of the SX-64, creating a [[Catch-22 (logic)|"catch-22"]] situation similar to [[Osborne effect|that endured by Osborne]] after announcing an improved version of its computer. The SX-64 did however gain a following with user groups and software developers, who could quickly pack and unpack the machine to use for copying software or giving demonstrations.

==Reception==
''[[Ahoy!]]'' favorably reviewed the SX-64, stating that the keyboard was better than the 64's, the monitor "isn't hard to read at all", and the disk drive was durable enough for travel. While criticizing the lack of any provision for internal or external battery power, the magazine concluded that the average $750–800 retail price was "worth every penny".<ref name="benford198502"/>

== Technical information ==
Like the [[Commodore 64]], except for the following differences:
* Built-in storage: {{nowrap|170 [[kilobyte|KB]]}} {{nowrap|5¼" [[floppy disk]]}} drive (internal version of the [[Commodore 1541]])
* Built-in display: 5" inch ({{nowrap|127 mm}}) [[composite video|composite]] color monitor ([[cathode-ray tube|CRT]])
* Keyboard: Separate unit, connected by cord to CPU unit
* Cartridge port: Placed on top of CPU unit, w/spring-loaded fold-in lid, cartridges inserted vertically (vs horizontally into back of C64)
* I/O connectors:
** [[Commodore bus|Serial "488" interface]] (rear)
** Video out connector (rear)
** User Port (rear)
** Cartridge Port (beneath two spring-loaded flaps on the case top)
** No [[Datassette]] interface
** No [[RF modulator]] & connector
** Non-standard 25-pin keyboard connector below right side of front panel. The connectors are similar but not identical to [[D-subminiature]] connectors and notoriously hard to find today{{Citation needed|date=November 2010}}
** Standard three-prong [[IEC 60320|IEC C14]] AC power connector (vs C64 DIN plug to "power brick" [[Power supply|PSU]])
* Power supply: Internal unit with transformer and rectifiers (vs external C64 PSU)
* Extra features: Floppy disk storage compartment above disk drive which could be used to build in an extra floppy drive or compatible sized modem

== References ==
{{reflist}}

==External links==
*[https://commodore-sx-64.com/#serial_register SX-64 Serial register]
*[http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c64/sx-64/sx64schematics.zip SX-64 schematics (PDF format, zipped)]
*[https://web.archive.org/web/20080723154104/http://www.erikschubach.com/vintage/sx-64-paper-model.php Commodore SX-64 Paper Model]
*[http://diskpreservation.com Disk Preservation Project] Preserving original C64 hardware and software

{{CBM computers}}{{Authority control}}
{{Commons category|Commodore SX-64}}

[[Category:Portable computers|Comm6]]
[[Category:Commodore 64]]
[[Category:Computer-related introductions in 1983]]