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.
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. The directory structure was much simplified as a result. 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. While no graphic displays were supported by TSC software, some hardware manufacturers supported elementary graphics and pointing devices. All versions were text-based and intended for use on display devices ranging from printing terminals like the Teletype Model 33 ASR to smart terminals. It was also later ported to the Motorola 6809 that version was called Flex9.
The original version was for 8' floppy disks and the (smaller) version for 5.25' floppies was called mini-Flex.
