Storage DevicesCh. 4

Main MemoryI. Also known as Primary memory

or active memory or internal memory

II. Categorized as volatile and non volatile memories, RAM is volatile memory whereas ROM is non volatile memory

III. ExpensiveIV. Directly accessed by the CPUV. Faster data accessVI. Temporary storageVII. Connected computer through

slotsVIII. Smaller or limited storage

capacity

Secondary memoryI. Also known as additional

memory or back memory or external memory

II. Always categorized as non volatile memory

III. CheaperIV. Indirectly accessed by the CPUV. Slower data accessVI. Permanent storageVII. Connected computer through

cablesVIII. Larger or extendible storage

capacity

RAM (Random Access Memory)I. Volatile memoryII. ExpensiveIII. Faster data accessIV. Larger in sizeV. Temporary storageVI. Directly and easily access to

information stored in the RAMVII. CPU can perform read or write

operations on RAM VIII. Two types, SRAM and DRAM

ROM (Read Only Memory)I. Non volatile memoryII. CheaperIII. Slower data accessIV. Smaller in sizeV. Permanent storageVI. Indirectly and difficult access to

information stored in the ROMVII. CPU can only perform read

operation on ROMVIII. Three types, EROM, EPROM and

EEPROM

Static RAMI. Data does not need to be

refresh periodicallyII. Consume less powerIII. ExpensiveIV. Faster data accessV. Used in cache memoryVI. More reliable

Dynamic RAMI. Data needs to be refreshed

periodically II. Consume more powerIII. CheaperIV. Slower data accessV. Used in main memoryVI. Less reliable

PROM• One time

programmable (OTP)

• No erase function

EPROM• Reprogrammable• Erased with UV

light

EEPROM

• Reprogrammable • Erased

electrically

Hard diskI. ExpensiveII. Modern technology III. Large storage capacity

(Increases day by day)IV. Faster data accessing and

transferring rateV. Larger in sizeVI. Heavyweight VII. Fixed in System unitVIII. Difficultly transportable IX. More reliable X. More Noisy

Floppy diskI. Very cheapII. Older technology III. Very small storage capacity IV. Slower data accessing and

transferring rate V. Smaller In size VI. Lightweight VII. Not fixed / portable VIII. Easily transportable IX. Less reliable X. Very less noisy