Computer Hardware

General classes of hardware :

• Input - used to get information into the computer. Includes keyboard, mouse, scanner, digitizer, digital camera, etc.
• Output - used to get information out of the computer. Includes monitor, printer, plotter
• CPU - Central Processing Unit. The brains of the computer - where the processing takes place.
  • RAM. Random Access Memory. Think of this as the active memory of the computer. Temporarily stores program instructions and data. The more RAM, the more stuff your computer can handle at once. Turn the computer off, and you lose everything that's in memory. For perspective, Vista systems require at least 2 GB of RAM, however, it is recommended that you purchase 4 (the max Vista can use).
  • ROM - Read Only Memory. This is your permanent memory. It stores the information required to boot up the computer.
  • Processor. This does the work. It gets info from RAM, changes it, and sends it back to RAM - where it can be accessed by the monitor or stored to a mass storage device.
  • Video card - this is the beastie that displays stuff on screen. It usually has it's own RAM to do the work. If you're a gamer, a 256 mb 3D chip will do what you need - at least this year. Beware those that are built into your motherboard - they cannot be upgraded. Thus, if purchasing a computer with a built-in video card, make sure the motherboard also has an AGP slot (where you can install your own video card). In the graphics world, including both gaming and GIS, be sure to buy systems with powerful graphics cards.
  • Bus speed: effectively how fast your computer can shuffle information from processor to RAM to video to harddrive, etc.. Most current systems are 32 bit - newer ones are 64. Beware 8/16 bit systems - they won't run much these days.

• Mass storage: Where you store your files. Harddrives (as of July, 2008, 1000 GB drives are available), CD (640 MB), floppy (1.44mb), DVD (up to 9 gb), Blu-ray DVD (25 GB), zip disks (100/250/750 mb), tape drives, etc... There are many many, many different ways of storing data - these are only the most common. Note, tape drives have become less and less common, zips are almost completely obsolete, floppys are useless, and most folks use USB flash drives as their portable storage medium.

Ports on back of computer

• Parallel. slow. typically, this is your printer port. being phased out. Newer computers no longer have them. Replaced by USB
• Serial. slow. being phased out. Now phased out, plug stuff into USB.
• SCSI. A fast connection, usually requiring a SCSI card being installed in your computer. Generates excess heat and are expensive. Pretty much obsolete these days.
• PCMCIA. Credit card sized cards plug into PCMCIA ports - usually found on laptops. Slowly being phased out, but you can still buy PCMCIA hardware.
• Video - this is where you plug in your monitor.
• PS2 - mouse/keyboard ports. Also being phased out. Again, gone on new computers. Replaced by USB.
• USB. The new standard for just about everything. Fast, simple.
• Firewire. The competitor to USB. Also very fast. Usually only found on Macs. Typically, firewire is a little faster than USB.