Search results
Results from the WOW.Com Content Network
The Bull Gamma 60, initially designed in 1957 and first released in 1960, was the first computer designed with multiprogramming in mind. Its architecture featured a central memory and a Program Distributor feeding up to twenty-five autonomous processing units with code and data, and allowing concurrent operation of multiple clusters.
Time-sharing was first proposed in the mid- to late-1950s and first implemented in the early 1960s. The concept was born out of the realization that a single expensive computer could be efficiently utilized by enabling multiprogramming, and, later, by allowing multiple users simultaneous interactive access. [1]
In order to ensure high-speed processing, batch applications are often integrated with grid computing solutions to partition a batch job over a large number of processors, although there are significant programming challenges in doing so. High volume batch processing places particularly heavy demands on system and application architectures as well.
In non-interactive execution (batch processing), a task is a unit of execution within a job, [1] [2] with the task itself typically a process. The term "multitasking" primarily refers to the processing sense – multiple tasks executing at the same time – but has nuances of the work sense of multiple tasks being performed at the same time.
These programs might take hours to run. As computers grew in speed, run times dropped, and soon the time taken to start up the next program became a concern. Newer batch processing software and methodologies, including batch operating systems such as IBSYS (1960), decreased these "dead periods" by queuing up programs ready to run. [4]
Layer 0 was responsible for the multiprogramming aspects of the operating system. It decided which process was allocated to the central processing unit (CPU), and accounted for processes that were blocked on semaphores. It dealt with interrupts and performed the context switches when a process change was needed. This is the lowest level.
Specifically, a program is sequentially consistent if "the results of any execution is the same as if the operations of all the processors were executed in some sequential order, and the operations of each individual processor appear in this sequence in the order specified by its program".
[8] [9] Debugging programs was an important problem at that time, because with batch processing, it then often took a day from submitting a changed code, to getting the results. John McCarthy wrote a memo about that at MIT, after which a preliminary study committee and a working committee were established at MIT, to develop time sharing.