Memory

Memory: It is used to perform the calculation/data manipulation. It is temporary work area. The data on the memory will be lost when is system is powered off. Volatile memory is computer storage that only maintains its data while the device is powered. Mostly RAM is used for primary storage in personal computer which is a volatile memory. To provide high availability the memory is inserted into different slots. (don't buy 32 GB RAM sticks instead 4 sticks of 8 GB is recommended). Memory is measured in megabytes(MB), gigabytes(GB).

Computer storage:

The data is stored in BITS and bytes. (bits are 0 & 1)

8 bits = 1 byte

1024 bytes = 1 KB (Kilobyte)

1024 KB = 1 MB (Megabyte)

1024 MB = 1 TB (Terabyte)

1024 TB = 1 PB (Petabyte)

1024 PB = 1 Exabyte

1024 Exabytes = 1 Zettabyte 
1024 Zettabytes = 1 Yottabyte 
1024 Yottabytes = 1 Brontobyte
1024 Brontobytes = 1 Geopbyte

Storage: Storage it is used to store the data consistently and it is non volatile. It is measured in GB, TB etc.  Disc performance depends upon the disc speed rpm (revolutions/rotations per minute). 5600/7200/10000/15000 rpm. Servers generally use 15000 rpm and laptops uses 5600 rpm.

Hard disc of various types: IDE, SCSI, SATA, SAS.

To get more performance (IOPS - input output per second) (eye OPS) by more than a single disc.

Ex: 1TB disc is not recommended instead 300 GB x 4 are recommended which will be also used for fail over. 

Network cord: It is a gateway for the computer to communicate with external world. It is used to provide connectivity with external systems. It would be either LOCAL, WIDE, METRO AREA NETWORK (LAN/WAN/MAN) to provide high availability more than one network cord is installed.

Each network cord he is unique and contains its own MAC (Media Access Control) address.

System: The collaboration of CPU, memory, disc and Ethernet code plugged on to your mother board is referred as a system.

The system is identified by its unique name referred as host name. The hostname details are maintained in a file/etc/hosts. The system is hardware which requires software to operate it.

Operating system: It is a set of commands, libraries, executables which are programmed in C, C++,VC++ and java etc.