MICROCOMPUTERS: A BASIC INTRODUCTION
Computers are becoming a necessity for the fire service rather than a luxury, Fire departments must be willing to change their procedures and take advantage of computers to enhance their operations. In order to purchase a computer system, you will need a basic understanding of computer terminology.
Personal computers. In 1981 International Business Machines Corporation (IBM) announced its first microcomputer— the IBM Personal Computer, or PC, for short. Soon other companies started to clone the IBM PC, and those computers became known as “PC compatibles.” Today the term PC generally is used to refer to all IBM PCs and compatibles.
The PC is the most used microcomputer in industry, offices, homes, and the fire service. However, there are other computer types on the market today that are not PC compatible. These generally will not run programs that were designed and written for PCs. With the use of hardware and software emulators, PC-tvpe software can be made to run on these other computers. The main computer that falls into this category is the AppleMacintosh, commonly referred to as the “Mac.” There are a number of fire departments using Macintosh computers and a few using other types. The PC and Mac both have fire service software available.
Hardware. The microcomputer, its components, and its peripherals are referred to as hardware. The microcomputer itself actually consists of many components such as the microprocessor, memory, disk drives, video monitor, keyboard, and mouse. External devices, known as peripheral equipment, such as printers, plotters, scanners, and external modems and disk drives, can be connected to a microcomputer.
Microprocessor. The microprocessor or central processing unit (CPU) is commonly referred to as the computer’s “brain.” It executes the instructions of any software application product (program).
Memory. Memory can be looked at as “storage cells” for the purpose of storing the instructions of a computer application and/or data. There are two kinds of memory: ROM and RAM.
ROM, read-only memory’, is used to contain the basic instructions that help the microcomputer function, such as booting (or starting) the microcomputer, and to provide special functions for all software packages. ROM memory does not lose its contents when the computer is turned off—the instructions are “burned” into the memory.
RAM. random-access memory, is used as temporary storage for programs and/or data. When power is turned off. this type of memory is erased. However, there are some RAM memory chips that can retain contents when the power is off, plus there are some systems that use a battery backup facility to retain their contents. RAM memoryis used for main, extended, and expanded memory.
The sizes of both types of memory are discussed in terms of kilobytes (K) and megabytes (MB). A byte is the basic unit of storage for a microcomputer. A kilobyte has 1,024 bytes. If you see an ad that says a computer has 512K of memory, then it has 512 X 1,024 bytes, or 524,288 bytes of storage. A megabyte has 1,024K of memory, or 1,024 x 1,024 or 1,048,576 by tes. Most microcomputers sold today have at least 1MB of RAM storage, with many providing 2 to 4MB as standard. Keep in mind that programs are requiring more and more memory, and it is less expensive to purchase a computer with a sizable memory than to later add peripheral memory equipment.
Add-in boards. In addition to the microprocessor and memory, the microcomputer itself also has a number of other internal components, mainly add-in boards. These boards provide the support to drive video monitors, disk drives, printers, and modems. These boards generally come as part of the complete microcomputer system. However, replacement boards as well as additional ones can be added in later as needed.
Disks and disk drives. One type of disk drive is the floppy drive with its flexible/removable diskettes. These were the onlydrives available on the first PCs. In fact, some microcomputers available today come with just floppy drives. Information can be written to and read from floppy disks. Floppy disk storage is referred to as external storage or mass storage. Floppy drives also allow a user to back up data that are contained on another type of disk drive, the hard drive.
Floppies come in various size diskettes with different recording densities (the amount of information that can be recorded on the surface of a diskette). Although diskettes with lower densities were used on the original PCs, those mentioned below are sold today.
The 5‘A” floppy comes in a 360K and a 1.2MB version. The 1 2MB drive can read either capacity diskette; however, the system manual has a warning about writing 360K diskettes on a 1.2MB drive. In most cases it will work.
The 3 ½” size also comes in two familiar densities: 720K (or HOOK for a Mac) and 1.44MB. The 1.44MB drive can read and write either density. I know of no restriction or warning as in the case of the 5¼”. Most microcomputers come with either the 1.2MB or 1.44MB drive, and some come with one of each.
Hard disk drives, or simply hard drives, are high-capacity mass-storage devices. The hard drive consists of one or more rigid platters (recording surfaces), which are fixed inside a sealed casing. This is sometimes referred to as nonremovable mass storage. Just as with the floppies, hard drives also come in various sizes and densities. Hard drives are generally 5 ⅛”, 3 ½”, or 2″. Their capacities first started at 5MB, but drives today come in capacities exceeding 200MB, and larger capacities are becoming available almost daily.
Video monitor. This is the microcomputer’s display screen. The very first microcomputers actually used regular TV monitors. Today the video monitors are more sophisticated, supporting many colors and screen densities. The greater the screen density, the better the images. Very high density monitors are used for computeraided design, while the lower-density monitors are excellent for general computer use —word processing, spreadsheet applications, and data base systems including those for the fire service. Monitors today are usually compatible for EGA (enhanced graphics adaptor) or VGA (vector graphics array), with the VGA becoming more and more the standard.
Either w ill work fine with most fire service software.
Keyboards. They come in various designs, but they are all basically the same. Any keyboard that comes w ith the microcomputer you purchase will work with any fire service software that I have seen.
I mentioned the mouse as part of a microcomputer. A mouse is a pointing device used to select applications to execute, request help screens, request menus, highlight information, and many other functions. For PCtype machines it is optional, although more and more are coming with a mouse. For the Macintosh, it’s included, as Macintosh software is designed with the mouse in mind.
Printers. Just as with the other components/devices, printers come in many shapes, styles, types, and performance levels. The two most widely used types are the dot matrix and laser. Dot matrix printers are the most common and the least expensive. They use either 9 or 24 pins in the print head that press the ribbon against the paper to form the desired characters or graphics. Apple has the Imagewriter LQ printer, which has 27 pins. Most dot matrix printers have either near letter quality or letter quality and draft mode.
Laser printers are high-resolution printers producing very high quality characters plus graphic images. They use laser technology to fuse ink to the paper.
Modem. The modem is one external device that the fire service might find very beneficial. A modem allows one computer to communicate with another via phone lines. For the fire service it could mean sending fire incident reports to the state fire marshal’s office, getting on-line support from softw are vendors, and communicating with fire service bulletin board services such as CHEMTREC and ICHIEFS.
Software. Microcomputers today come with a software program called the Operating System. It’s a system level program that allows the application programs to conveniently access the microcomputer’s resources. Resources include the disks, memory, video monitor, keyboard, and external devices.
Application software products are programs designed to provide the users with the functions they w ant to perform, such as payroll, accounting, record keeping, word processing, reports, information files, and more.
Minimum requirements. For running most software, including fire service applications, a microcomputer with 1MB of RAM as a minimum, a 20-40MB hard drive, at least one floppy drive, a monochrome video monitor, and a printer are all that you need to get started. Modems, more memory, a mouse, additional floppy drives, and other components all can be added later to enhance your system.