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The 155 was one of the first of the 370 series. A replacement for the 360-50 It used the new monolithic integrated circuits (MST) but still had core for main storage. The 155 introduced the 370 instruction set with the addition of 14 new instructions. A maximum storage of 2 Megabyte and a cycle time of 2.1 Microseconds, with a 16 Byte wide parallel data flow.  Storage was located in 3360 storage frames a maximum of four  with half a Meg of storage in each. The 155 also had an 8 K Byte high speed monolithic storage buffer this had a 60 nanosecond cycle time and acted as transparent cache so reducing the effective cycle time of processor storage. The CPU had a 115 nanosecond cycle time and a four byte data flow. The CPU and I/O were controlled by CROS read only storage with cycle time of 69 nanoseconds.

I/O was via one or two Byte Multiplexer channels for slow speed devices and up to five of the new Block Multiplexer channels for high speed. See Standard Interface for details of channels. One Channel to Channel Adapter (CTCA) could be installed as a feature. This allowed for another 360 or 370 systems to  be interconnected.

The1052 typewriter consul that had bean used in the 360 range was replaced with a either a 3210 or 3215 Console printer keyboard.

The 3155-1 did not have Dynamic Address Translation (DAT). But could be field upgraded to 3155-11 this then allowed virtual storage to be used up to 16 Meg.

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This page was last edited on 10/02/00