Looking Inside the Box
Most of the processing and storage devices show up "inside the box." This section gives you a look at the major elements that you will find inside the system housing, or case.
Processor/CPU
The processor (also known as the Central Processing Unit, or CPU) is the "brains of the organization," so to speak. It is designed to do very few things, but to do them extremely quickly. The processor performs a limited set of calculations based on requests from the operating system and controls access to system memory. Processor speed is measured in several different ways, including clock cycles, megahertz (MHz), and Millions of Instructions Per Second (MIPS). Any of these measures give you an estimate of the processor's power.
The speed of early processors ranged from 4 MHz to 8 MHz, while today's processors have broken the multi-gigahertz (GHz) mark.
Storage devices
Storage devices on your computer are responsible for storing data, such as the operating system, applications, and actual output of applications or user data. Depending on the amount and type of data, there are five basic types of devices to work with:
- Floppy drives, including some of the high-capacity formats (such as 120MB Superdisks)
- Hard drives, including some of the removable cartridge drives (such as SyQuest drives)
- Optical drives, including CD-ROM and DVD drives
- Magnetic tape drives, which come in a variety of capacities and are usually used for archiving data
- Flash drives, which store data in a variety of non-volatile memory chips
Any one of these formats enables your computer to store and retrieve data. Each of these storage options is considered to be long-term or permanent storage, but that term is relative as each media format has a limited lifespan.
When dealing with storage devices, there are three major technologies used to connect hard drives to motherboards: IDE (Integrated Device Electronics) or ATA (AT Attachment), SATA (Serial ATA), and SCSI (Small Computer System Interface). An ATA controller allows the 40-pin IDE connector to accept a wide variety of devices, while maintaining full backward compatibility with tradition IDE drives or devices. In most cases, IDE and ATA are used interchangeably, while the current systems are technically using ATA technology. There has been a long ongoing battle for speed and performance between IDE (or ATA) and SCSI, but in general, SCSI provides faster and more reliable transportation, while IDE has been the low-cost alternative. SATA is IDE's new cousin, and will help IDE's fight to challenge the benefits of SCSI.
Do not forget that ATA and IDE terms are used interchangeably, but you do not want to confuse these terms with Serial ATA, which uses different technology.
Within a computer a bus is a mechanism that is used to move data between devices of the computer, much like a city bus is used to move people between bus stops in the city. Hard drives are manufactured as ATA, SATA, or SCSI devices, and they are usually connected to the motherboard through the high-speed PCI (Peripheral Component Interconnect) bus but being internal devices cannot be easily transported between computers. The USB, IEEE 1394 (or FireWire), and PCMCIA (PC Card) buses provide fast-enough data transfer to allow hard drives to be attached to a system using these technologies, and are designed to be used with external devices. There are many manufactures that have products that allow standard ATA or SATA drives to be connected using these buses. Due to the higher cost and the difference in technology, SCSI drives are not normally used.
The type of drives that you can attach to your computer depends on the types that are supported by your motherboard and I/O cards.
