second generation computer

1 definition found

second generation computer - Free On-line Dictionary of Computing (26 May 2007) :

  second generation computer
  
     <architecture> A computer built from transistors, designed
     between the mid-1950s and mid-1960s.
  
     Ferrite core memory and magnetic drums replaced cathode ray tubes
      and delay-line storage for main memory.  Index registers
      and floating point arithmetic hardware became
     widespread.  Machine-independent high level programming languages
      such as ALGOL, COBOL and Fortran were
     introduced to simplify programming.
  
     I/O processors were introduced to supervise input-output
     operations independently of the CPU thus freeing the CPU
     from time-consuming housekeeping functions.  The CPU would
     send the I/O processor an initial instruction to start
     operating and the I/O processor would then continue
     independently of the CPU.  When completed, or in the event of
     an error, the I/O processor sent an interrupt to the CPU.
  
     Batch processing became feasible with the improvement in I/O
     and storage technology in that a batch of jobs could be
     prepared in advance, stored on magnetic tape and processed on
     the computer in one continuous operation placing the results
     on another magnetic tape.  It became commonplace for
     auxiliary, small computers to be used to process the input and
     output tapes off-line thus leaving the main computer free to
     process user programs.  Computer manufacturers began to
     provide system software such as compilers, subroutine
     libraries and batch monitors.
  
     With the advent of second generation computers it became
     necessary to talk about computer systems, since the number of
     memory units, processors, I/O devices, and other system
     components could vary between different installations, even
     though the same basic computer was used.
  
     The instruction repertoire of the IBM 7094 (a typical second
     generation machine) had over 200 instructions including data
     transfer instructions for transferring a word of information
     between the CPU and memory or between two CPU registers;
     fixed-point and floating point arithmetic instructions;
     logic instructions (AND, OR etc.); instructions for
     modifying index registers; conditional and unconditional
     branching; subroutines; input-output operations for
     transferring data between I/O devices and main memory.
  
     (1996-11-25)