Internal Memory
CPU can only store data and instructions in the register of small size , so can not store all the information needed for the entire process from the program. To overcome this, the device is equipped with process main deposits (Main storage) or internal memory. The size of main memory in bytes is determined. Memory play consists of Random Access Memory (RAM) and Read Only Memory (ROM).
RAM (Random Access Memory)
RAM is memory that can be accessed, the structure of the RAM is divided into 4 (four) parts, namely:
1. Input Storage, used to accommodate the input is entered via input devices.
2. Storage Program, is used to store all the program instructions to be processed.
3. Working Storage, used to store data to be processed and the results of the processing.
4. Storage output, used to accommodate the end result of processing the data to be displayed on output devices.
Input is entered through the input device, the first time it first accommodated in the input storage, if the input shaped the program, then transferred to a storage program, and if the shape of the data will be transferred to working storage. The results of the processing is also accommodated in the working storage and the results will be displayed to the output is transferred to output storage.
ROM (Read Only Memory)
ROM is memory that can only be read only. The contents of the ROM was created from the manufacturer, in the form of operating system consisting of basic programs required by the computer system and the bootstrap program.
Bootstrap program required the first time a computer system is activated, a process referred to as booting. The contents of the ROM should not be lost or damaged, if this happens, the computer system will not work, the contents of ROM are permanent, meaning the contents of ROM will not be lost if the computer is turned off power.
Main memory Type
Vacuum Tube , Used on first-generation computers (1946) as the main memory. Each vacuum tube represents bit value 1. So if the main memory of 64 KB, then the vacuum tubes that required as many as 524,288 units. This is the first generation of computers resulted in a large size.
Magnetic Core Storage , Consisting of thousands of small magnetic ring diameter 18 mm and 10 mm hole, intangible like donuts. Each core can store 1 bit.
Planar Thin Film Storage , Made of thin ceramic plates embus view a collection that contains nickel-iron rectangular.
Semiconductor Storage , Storage is Volatile Semiconductor (contents of memory will be lost if the electricity does not enter). The shape of the chip can accommodate 64 KB served until capacity with 64MB
Josephson Junction , Having speed billion seconds, to get the speed of this circuit should be enclosed in a place that contains the liquid helium, so it will be cooled close to 0 degree Kelvin (= minus 200 degrees Celsius).
