Cursuri Computer Architecture

1943-1946

Electronic Numerical Integrator And Computer

18.000 vacuum tubes

30 tones

150 m2

140 kW

Decimal

5000 additions per second

John von Neumann

Power Source

Circuit Board - MotherBoard

Processor

Memory Slots

Chips

Rear/Front Connectors

Sockets where the edge connectors of I/O boards can be inserted

The job of a controller is to control its I/O device and handle bus access for it.

When a program wants data from the disk for example, it gives a command to the disk controller, which then issues seeks and other commands to the drive. When the proper track and sector have been located, the drive begins outputting the data as a serial bit stream to the controller. The controller breaks the bit stream up into units and sends them further.

A controller that reads or writes data to or from memory without CPU intervention performs DMA (Direct Memory Access).

When the transfer is completed, the controller normally causes an interrupt, forcing the CPU to suspend running its current program and start running a special procedure, called an interrupt handler, to check for errors, take any special action needed, and inform the operating system that the I/O is now finished. When the interrupt handler is finished, the CPU continues with the program that was suspended when the interrupt occurred