Commodore SX-64

The SX- 64, also known as the Executive 64, was a portable version of the C64. It contained a built-in 5 " (127 mm) color screen and one for VC1541 compatible 5 ¼" floppy disk drive. The computer did not contain a battery, and was run at normal power grid, weighed 10.5 kg and had loud advertising text under an airplane seat.


The SX- 64 was from December 1983 at a price of 995, - sold U.S. $ in Germany was offered the unit from the spring of 1984 for just under 3,000 DM. The device was sold only in the period spring 1984 until 1986. Contrary to persistent rumors more than 49,000 copies worldwide produced and distributed, which can be easily seen in the ongoing series number. 's SN Database on you find a SX -64 with the end number 049807 originally planned Commodore a double - disk drive for the device, at the Summer CES (Consumer Electronics Show ) 1983 in Las Vegas, we therefore propose a suitably equipped prototype. The designation chosen initially Commodore Executive Double Drive 64 short DX -64 was born. Besides this prototype could still prove no salable product. At the Winter CES a nearly production-ready prototype was presented, which only had a floppy drive and the accordingly changed names SX -64 ( Single DriveExecutive 64) got. The second drive, which probably cost reasons, the red pencil fell victim, but should be able to be ordered optionally. It has been a further prototype presented, the SX -100, a largely similar device, only equipped with a black and white monitor. But this did not progress beyond the prototype stage.

The DX - 64 is indeed occasionally mentioned in the attached manual, also seen in a device description, a drawing of a computer with dual-drive, however, so that the Double DriveExecutive 64 is a "real " production model of the DX -64 today is not occupied, it has probably never brought to the market, only DIY projects can be found on the internet, easy to recognize the fact that the top drive on the front panel has the name STORAGE.

Areas of application

In fact, the SX- 64 was at that time used as a " representative laptop ". Thanks to the color monitor were the times the representation of plain text over, you could now give to the field staff also elaborate graphics. Programs such as Multidata64, CalcResult64, Adressen64, Mitgliederverwaltung64 and Text64 aimed at office applications, warehouse management and similar applications in companies. There were so many professional applications for the device. The traffic light system company SILA used the SX -64 to control and program their mobile use traffic lights at construction sites. The company CIL Microsystems of Sussex / England offered a modified SX -64 as a measurement and control computer for the technical and scientific area, the shaft above the drive through a data interface (ADS - Interface) has been replaced, the four analog inputs, two analog outputs, four digital TTL and four relay outputs included. The Tesa sent their sales representatives with specially modified devices called " Scotch Label Printer 6240 " to the customers. The monitor was replaced by a green screen, the SID, which is responsible for the sound in the SX -64 has been removed, as are the controls for volume, brightness, contrast and color. The ROM contained a special Tesa software.


The keyboard of the SX -64 was removed, had 66 keys QWERTY arrangement and also served as the cover of the computer case. It was connected via a cable with two 25-pin, D -sub connectors similar. Since we had planned the floppy drive firmly into the device, the engineers dropped it Datassettenport. Also accounted for is no longer required command routines for the tape in ROM. However, the retired technical problems: External peripherals, such as the in-house parallel Centronics printer interface, which used this port as a power supply could not be used here. Also, some programs refused their service, because they interpreted the missing datasettes routines in the kernal as an error of the computer. Another problem brought the power supply with it. In early versions of the SX -64 was designed so scarce that Commodores own RAM Expansion Unit ( REU) refused their service, because they are not received enough energy from the power supply. The weak power supply is also the probable reason why the second drive of the originally presented Double DriveExecutive 64 obviated energy supply would collapse if both drives are addressed simultaneously. However, the power supply problem has been corrected in the first device revisions. Just like the C64 possessed the SX -64 over 64 KB of RAM. The default colors for font has been changed in blue on a white background to improve readability on the small screen.


The SX- 64 has striking similarity to the Osborne 1, which was published two years ago, and still won an award for industrial design. The term " portable computer " has manifested itself through such devices for the first time. Even if the battery-free computer apply in the modern sense as not portable, they were the first mobile computer.

Differences for C64

  • Portable version
  • Built-in 1541 floppy
  • Changed Kernal ROM without datasettes routine
  • Built-in monitor unit speakers including
  • No connection for Datasette
  • No RF output for TV
  • Built in power supply
  • Module bay above


  • Construction period: 1983-1986
  • Processor 6510, 8 bit
  • Clock Frequency: 0.99 MHz
  • RAM: 64 KB (expandable to 512 KB)
  • ROM: 20 KB
  • Operating System: Basic 2.0 ( in ROM)
  • Screen resolution: 320 × 200 graphics, 160 × 200, text: 40 × 25
  • Colors: 16
  • Sound: 3-channel, mono
  • Interfaces: Serial 1 round ( CBM - Bus), 1 Video / Audio, 1 User Port, 2 joystick or mouse, 1 module slot
  • Keyboard: 66 keys
  • Built drives: Floppy 5 ¼ " to VC1541 compatible
  • Special features: built-in 5 "color screen, built-in power supply, no battery