Ibm 704

The IBM 704, the first mass-produced Computer with Floating Point arithmetic hardware, was introduced by IBM in April, 1954 . The 704 was significantly improved over the IBM 701 in terms of architecture as well as implementation, and was not compatible with its predecessor.

Changes from the 701 included the use of Core Memory (instead of Williams Tube s) and addition of three Index Register s. To support these new features, the instructions were expanded to use the full 36-bit word. The new Instruction Set became the base for the IBM 700/7000 Series scientific computers.

To quote the IBM 704 ''Manual of operation'' (see external links below):

:The type 704 Electronic Data-Processing Machine is a large-scale,
:high-speed electronic calculator controlled by an internally stored
:program of the single address type.

IBM stated that the device was capable of executing up to 40,000 instructions per second. IBM sold 123 type 704 systems from 1955 to 1960.

The programming languages FORTRAN and LISP were first developed for the 704, as was MUSIC 1, the first computer music program by Max Mathews .

In 1962 physicist '' computer sings the same song as he is being put to sleep by astronaut Dave Bowman . Bell Labs: Where "HAL" First Spoke (Bell Labs Speech Synthesis website)

INSTRUCTION AND DATA FORMATS

The basic instruction format was a 3-bit ''prefix'', 15-bit ''decrement'', 3-bit ''tag'', and 15-bit ''address''. The prefix field specified the class of instruction. The decrement field often contained an immediate Operand to modify the results of the operation, or was used to further define the instruction type. The three bits of the tag specified any combination of three "decrement registers", an early kind of '' Index Register s'' in which the contents of the registers were subtracted from the address to produce an Effective Address . The address field either contained an address or an immediate operand.

Fixed point numbers were stored in binary Sign/magnitude Format .

Single precision Floating Point numbers had a magnitude sign, an 8-bit excess-128 exponent and a 29 bit magnitude

Alphanumeric characters were 6-bit BCD , packed six to a word.

CITED REFERENCES

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Ibm 704