FLEX (operating system)

Infobox OS
name = FLEX



caption =
developer = Technical Systems Consultants
source_model =
kernel_type =
supported_platforms = Motorola 6800, Motorola 6809
ui = Command line interface
family =
released = 1976
latest_release_version =
latest_release_date =
latest_test_version =
latest_test_date =
marketing_target =
programmed_in =
prog_language = BASIC, FORTH, C, FORTRAN, and PASCAL
language = English
updatemodel =
package_manager =
working_state = Historic
license =
website = The FLEX single-tasking operating system was developed by Technical Systems Consultants (TSC) of West Lafayette, Indiana, for the Motorola 6800 in 1976. [ [http://www.flexusergroup.com/flexusergroup/fug3.htm FLEX User Group - History ] ] The original version was for 8" floppy disks and the (smaller) version for 5.25" floppies was called mini-Flex. It was also later ported to the Motorola 6809; that version was called Flex9. [ [http://www.flexusergroup.com/flexusergroup/fug10.htm FLEX User Group - FAQs ] ] All versions were text-based and intended for use on display devices ranging from printing terminals like the ASR-33 to smart terminals. While no graphic displays were supported by TSC software, some hardware manufacturers supported elementary graphics and pointing devices.

It was a disk-based operating system, using 256-byte sectors on soft-sectored floppies; the disk structure used linkage bytes in each sector to indicate the next sector in a file or free list. The directory structure was much simplified as a result. TSC (and others) provided several programming languages including BASIC in two flavors (standard and extended) and a tokenizing version of extended BASIC called Pre-compiled BASIC, FORTH, C, FORTRAN, and PASCAL.

TSC also wrote a version of FLEX, "Smoke Signal DOS", for the California hardware manufacturer Smoke Signal Broadcasting; this version used forward and back linkage bytes in each sector which increased disk reliability at the expense of compatibility and speed.

Later, TSC introduced the multi-tasking, multi-user, Unix-like uniFlex operating system, which required DMA disk controllers, 8" disk, and so sold in only small numbers. Several of the TSC computer languages were ported to uniFlex.

During the early 1980s, FLEX was offered by compusense ltd as an operating system for the 6809-based Dragon 64 home computer.

References

External links

* [http://www.evenson-consulting.com/flexusergroup/fug1.htm FLEX User Group]
* [http://www.rtmx.com/UniFLEX The Missing 6809 UniFLEX Archive]