DMAF-1 Floppy Disk System

The DMF-1 is a dual drive floppy disk sys�tem using double sided 8 inch diskettes. Both drives have dual heads to allow access to both sides of the diskette without re�moving the diskette and turning it over. Each diskette is capable of storing up to 600,000 bytes of formatted data, giving a total "on line" storage capacity of 1.2 million bytes. The drives are controlled by a direct memory access (DMA) controller sys�tem. The controller plugs into one of the unused memory slots in the SWTPC 6800 computer. A fifty conductor ribbon cable connects the controller to the drives. The controller will operate up to four drives.

The DMF-1 disk system requires a minimum of 24K of memory to operate. The DOS requires 8K of memory located at an address beginning at A000 hex. We recommend use of the 68/40 computer with this system. This provides 32K of user memory and the 8K for the DOS in the correct address location.

The DMF-1 system is supplied with Flex, a powerful and flexible but easy to use operating system. Programs and data files are accessed and manipulated using file names and extensions. The operator need not specify, or even be aware of tracks, sec�tors, file numbers, etc. as is necessary in less elegant systems. A full feature disk BASIC with both sequential and random file hand�ling is also included. Both BASIC and Flex incorporate access to a spool file system that allows printer operation to occur indepen�dently of computer use and at any desired time.

The system includes the cabinet, power supply, DMA controller, connecting cable, diskette with software, instruction manual and two drives. Size is 17 x 5 3/8 x 20 1/2, and shipping weight is 53 lbs. The drive expansion system includes all of the above except the controller.

DMF1 DMA Dual Disk System, Kit $2,000.00, Assembled $2095.00
Introduced by SWTPC in May 1978.

DMAF-1 Users Guide (2.6 MB PDF)


Disk Storage
Michael Holley's SWTPC Collection Home Page
This page was last edited August 14, 2013