a) RAM- Random Access Memory
It is a running workspace of computer. Initially, every task is stored in RAM, when we save these data, then these are stored in secondary memory. It is also called volatile memory because the information’s are erased when the power switch off. We have 128MB, 256MB, 1GB and 2GB memory at market.
b) ROM- Read Only Memory
it is the programming chips where all of the system information are kept at the time of manufactured. We can see the information of ROM: we time of booting. Even it can store the instructions even power is switch off. The program written on the ROM is also called as firmware. We can see all the information at booting period but we do not have access to change these instructions.
II. Secondary Memory:
Secondary storage devices hold files that are not currently being used. After editing the instructions and data are stored in secondary memory. It is such type of storage device that not attached with computer. There are different types of external storage device. These are given below.
Floppy disk
This is a secondary storage device. The size of the floppy is 3.5 inch. Its capacity is 1.44 MB. We can insert in the CPU and eject from CPU. We can save file in floppy and transfer to next computer. Nearly 14,57,664 characters can be stored in floppy disk.
Hard Disk
This is fixed disk which works as main memory of computer. All the files and programs are stored inside the hard disk. Technically hard disks are called Winchester disks or fixed disks, as they are pack of disk. Normally it can measure in gigabytes. We found 80 GB, 160 GB, 250 GB, 320 GB, 500 GB, 1Tb and 2 TB capacity hard disk.
CD
It stands for compact disc. We can store up to 720 MB in the CD. CD-R & CD-RW are available in the market. We can store songs, movies, computer files, programs and large data in the CD.
Pen Drive
This is very popular among IT experts or busy personalities because it is very simple to transfer data from one computer to another computer using pen drive. Up to 1GB-16GB capacity pen drive can be found in the market.
