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All computers require either fixed or removable storage for their operating
system, programs and user generated material. Formerly the 5 1/4 inch
and 3 1/2 inch floppy drive were the principal forms of removable storage
for backup of user files and distribution of software. But, as memory
sizes increased, the capacity of the floppy did not keep pace; the Zip
drive and other higher-capacity removable media were introduced but never
became as prevalant as the floppy drive. By the late 1990's the optical
drive, in CD and later DVD and Blu-ray Disc, became the main method for
software distribution, and writeable media provided backup and file interchange.
Floppy drives have become uncommon in desktop personal computers since
about 2000, and were dropped from many laptop systems even earlier. [11]
Early home computers used compact audio cassettes for file storage; these
were at the time a very low cost storage solution, but were displaced
by floppy disk drives when manfacturing costs dropped, by the mid 1980's.
A second generation of tape recorders was provided when video casssette
recorders were pressed into service as backup media for larger disk drives.
All these systems were less reliable and slower than purpose-built magnetic
tape drives. Such tape drives were uncommon in consumer-type personal
computers but were a necessity in business or industrial use.
Interchange of data such as photographs from digital cameras is greatly
expedited by installation of a card reader, which often is compatible
with several forms of flash memory. It is usually faster and more convenient
to move large amounts of data by removing the card from the mobile device,
instead of communicating with the mobile device through a USB interface.
A USB flash drive today performs much of the data transfer and backup
functions formerly done with floppy drives, Zip disks and other devices.
Main-stream current operating systems for personal computers provide standard
support for flash drives, allowing interchange even between computers
using different processors and operating systems. The compact size and
lack of moving parts or dirt-sensitive media, combined iwth low cost for
high capacity, have made flash drives a popular and useful accessory for
any personal computer user.
The operating system (e.g.: Microsoft Windows, Mac OS, Linux or many
others) can be located on any removable storage, but typically it is on
one of the hard disks. A Live CD is also possible, but it is very slow
and is usually used for installation of the OS, demonstrations, or problem
solving. Flash-based memory is currently expensive (as of mid-2008) but
is starting to appear in laptop computers because of its low weight and
low energy consumption, compared to hard disk storage.
These components can usually be put together with little knowledge to
build a computer. The motherboard is a main part of a computer that connects
all devices together. The memory card(s), graphics card and processor
are mounted directly onto the motherboard (the processor in a socket and
the memory and graphics cards in expansion slots). The mass storage is
connected to it with cables and can be installed in the computer case
or in a separate case. This is the same for the keyboard and mouse, except
that they are external and connect to the I/O panel on the back of the
computer. The monitor is also connected to the I/O panel, either through
an onboard port on the motherboard, or a port on the graphics card.
Several functions (implemented by chipsets) can be integrated into the
motherboard, typically USB and network, but also graphics and sound. Even
if these are present, a separate card can be added if what is available
isn't sufficient. The graphics and sound card can have a break out box
to keep the analog parts away from the electromagnetic radiation inside
the computer case. For really lar |
