As a program statement and data I received buying the cpu from an input device the results of the processed data are sent from the cpu to an output device. These results are transferred from the output storage onto an output medium. Some of the output units include video display unit printer floppy diskette and digital speakers amongst others.
STORAGE UNIT:
The main or primary memory storage units are ram and rom among others. Ram stands for random access memory and it is possible to randomly select and use any location of the memory directly to store and retrieve data. The storage of data and instruction inside ram is temporary . This is because its content disappears as soon as the power to a computer is switched off. For this reason, ram is said to be bolo tara. Ron is the ics inside the computer. Rom read only memory is another primary memory. Again it is the ics inside the computer that form the rom. The rom stores some standard processing program supplied by the manufacturers to operate the personal computer. The rom can only be read by the cpu but it cannot be changed. The basic input and output program that examines and analyses various equipment attached to the personal computers when the switch is made on is stored in the room. Room is said to be none volatile. The storage capacity of the main memory is very limited. Often it is very necessary to store hundreds of millions of bytes of data for the cpu to process. Therefore additional memory is required in the computer system. This memory is called auxiliary memory and secondary memory. The data stored in the secondary memories are transferred to the primary storage as and when required.
SECONDARY STORAGE MEMORY:
Secondary memories are required to help store additional data for the cpu to process. Some specific examples include among others hard disk floppy diskette compact disc and flash drive.
FLOPPY DISKETTE:
A floppy diskette is a data storage device that is composed of a disk of thin flexible floppy magnetic storage medium encased in a square or rectangular plastic shell. Floppy disk read and written by a floppy disk drive or fdd. Invented by ibm, floppy disk in it, 5.25, and 3.5 for max enjoyed many years as a popular and obvious form of data storage and exchange from the middle 1970s to the late 1990s. However they have now been largely supersede buy flash and optical storage device while email has become the preferred method of exchanging small to medium digital files.
Floppy disk also known as floppies or diskettes we are the suffix etta means little one we are obiquitous in the 1980s and 1990s being used on home and personal computers pc platforms such as the apple ii macintosh and ibm pc to distribute software, transfer data between computers and create small backups. Before the popularization of the hard drive for pcs floppy disk we are typically used to store a computer's operating system os applications software and other data. Many home computers had their primary os kernels stored permanently in onboard rom chips but stored the disk operating system on a floppy whether it proprietary system or later DOS. Since the floppy drive was the primary means of storing programs, it was typically designed as the a drive. The floppy drive was the drive and does with the luxury and off a hard drive we are designated the c drive, a convention that remains with us today long after the decline of the floppy disk utility.
Floppy disk size are almost universally referred to in imperial measurements even in countries where metric is the standard and even when the size is in facts defined in metric for instance 3/2 inch floppy which is actually 90mm. Formatted capacities are generally set in terms of binary kilobyte as 1 sector is generally 512 bytes. However recent sizes of floppy are often referred to in exchange hybrid unit, that is a 1.44 floppy is in fact 1.44 x 1000 x 1024 bite which is 1.41 mb or 1.47 medium bites other formats do exist such as 1.2 mb 5/4 inch floppy variations as well as other variations for the 3.5 inch floppy disk. External usb based floppy disk drive available for computers without floppy drives, and they work on any machine that supports usb mass storage device.
HANDLING OF FLOPPY DISKETTE:
Floppy diskette and the data stored on them are vulnerable to damage from mishandling for example that is from:
Magnetic fields.
Flexing or bending.
Excessive temperature.
Touching the magnetic surface.
Solvent or other reactive chemicals.
Removal of disk from a drive while in use.
Excessive amount of dust, smoke or other pollutants e.t.c.
HARD DISK DRIVE:
Strictly speaking drive refers to a device distinct from its medium such as a tape drive and its tape or a floppy disk drive and its floppy disk. A hard disk drive hdd commonly referred to as hard drive, hard disk fixed disk drive, is a known volatile storage device which stores digitally encoded data on rapidly rotating platters With magnetic surfaces. Early hdd's hard removable media, however, and hdd today is typically sealed unit with fixed media.
Hdd were originally developed for use with computers. In the 21st century applications for stds have expanded beyond computers to include digital video records, digital audio players, digital cameras, video game consoles. In 2005 the first mobile phones to include hdds we are introduced by samsung and nokia.
Hdds record data by magnetizing a ferromagnetic metal in a pattern that represent the data. They read the data by the texting the magnetization of the material. A typical hdd design consists of a spindle which holds one or more flat circular disc called platters onto which the data is recorded. The platters are made from non magnetic material usually glass or aluminium and are coated with a thin layer of magnetic materials. Older disk used iron 3 oxide as the magnetic material, but current disc use a cobalt base alloy.
Capacity of a hard disk drive is usually quoted in gigabytes. Older hdd quoted their smaller capacity in megabytes. The physical size of a hard disk drive is quoted in inches. The majority of hdd is used in desktops today 3.5 inches 9cm wide while the majority of those used in laptops are 2.5 in cm wide . As of early 2007, manufacturers have started selling sata and sas 2.5 inch for use in servers and desktops.
USB flash drives are NAND type flash memory data storage device integrated with a usb universal series bus Interface. They are typically small lightweight removable And rewritable. Usb memory card readers are also available, whereby rather than being built in, the memory is a removable flash memory card housed in what is otherwise a regular usb flash drive. Usb flash drive offer potential advantages over other portable storage device particularly the floppy disk . They are more compact, faster, hold more data, and are more reliable due to their lack of moving parts and more durable design. Additionally, it has become increasingly common for computer to ship without floppy disk drives. Usb ports , on the other hand appear on almost every current main screen pc and laptop. These types of drives used the usb mass storage standard, supported natively by modern operating systems such as windows, mac os linux unix and others.
A flash drive consists of a small pointed circuit board typically in a plastic or metal casing making the drive sturdy enough to be carried about in a pocket as a key fob or on a lanyard . Only the usb connector protrude from this protection, and is usually covered by a removable cap or by retracting into the body of the drive. Most flash drives use a standard type a usb connection allowing them to be connected directly to a port on a personal computer.
To access the data stored in flash drive, the flash drive must be connected to a computer, either by plugging it to a usb host controller built into the computer, or into a usb hub. Flash drives are active only when plugged into a usb connection and drawn all necessary power from the supplier provided that connection . However, some flash drives, especially high speed drives may require more power than the limited amount provided by a bus powered usb hub, such as those built into some computer keyboard or monitors. This drives were not work unless plugged directly to a host controller that is the port found on the computer itself or a self-powered hub.
Some of the common areas of usage includes:
System administration. Flash drives are particularly popular among system and network administrators , who load then which configuration information and software used for system maintenance, troubleshooting, and recovery.
Computer repair. Flash drives enjoy notable success in the pc repair field as a means to transfer recovery and antivirus software to infected pcs while allowing a portion of the host machine's data to be achieved in case of emergency.
Application careers. Flash drives are used to carry applications that run on the host computer without requiring installation.
To boot operating system. In a way similar to that used in live cd one can launch any operating system from a bootable flash drive known as a live usb.
Windows vista readyboost. In windows vista, readyboost features allow use of some flash drives to augment system memory.
Personal data transport. The most common use of flash drive is to transport and store personal files such as documents, pictures and video. Individuals also store medical alert information on media tag flash drives for use in emergencies and for disaster preparation.
Audio players. Many companies make solid state digital audio players in a small form factor, essentially producing flash drives with sound output and a simple user interface.
