Terminology

C

Communications Register Unit: serial interface embedded in TMS processors

CRU: short for Communications Register Unit

D

Device Service Routine: Program that is provided for accessing a peripheral device; would be called a driver in common terminology. The DSR defines device names and functions to operate the device on a higher level, abstracting from the hardware details. There are utility functions in the BASIC ROM and for assembly language programs to facilitate accessing the DSR of a device given by name (DSRLNK). The DSR is usually stored in a ROM circuit that was included on the PCB of the expansion card. Each card may be selected by a CRU operation which leads to the DSR being mapped into the CPU address space. The common region for DSRs is >4000 to >5fff. On the Geneve, DSRs are also included as parts of the MDOS operating system, replacing the fixed DSRs on the ROMs.

DSR: see Device Service Routine

F

Firehose cable: Nickname for the Flex Cable Interface

Flex Cable Interface: Card, cable, and plug that connect the TI-99/4(A) console with the Peripheral Expansion Box. The Flex Cable Interface's card was usually plugged into slot 1 of the P-Box.

I

ISR: see Interrupt Service Routine

P

P-Box: short for Peripheral Expansion System Box or Peripheral Expansion Box