Peripherals SDS Sigma series

1 peripherals

1.1 mass storage
1.2 communications
1.3 system control unit

peripherals

input/output accomplished using control unit called iop (input-output processor). iop provides 8-bit data path , memory. systems support 8 iops, each of can attach 32 device controllers.

an iop can either selector i/o processor (siop) or multiplexer i/o processor (miop). siop provides data rate 1.5 megabytes per second (mbps), allows 1 device active @ time. miop, intended support slow speed peripherals allows 32 devices active @ time, provides .3 mbps aggregate data rate.

mass storage

rad cover open , disk pulled out maintenance

the primary mass storage device, known rad (random-access disk), contains 512 fixed heads , large (approx 600 mm/24 in diameter) vertically mounted disk spinning @ relatively low speeds. because of fixed head arrangement, access quite fast. capacities range 1.6 6.0 megabytes , used temporary storage. large-capacity multi-platter disks employed permanent storage.

communications

the sigma 7611 character oriented communications subsystem (coc) supports 1 7 line interface units (lius). each liu can have 1 8 line interfaces capable of operating in simplex, half-duplex, or full-duplex mode. coc intended low medium speed character oriented data transmissions.

system control unit

the system control unit (scu) microprogrammable data processor can interface sigma cpu, , peripheral , analog devices, , many kinds of line protocol. scu executes horizontal microinstructions 32-bit word length. cross-assembler running on sigma system can used create microprograms scu.