Computer Hardware

 

 

Graphics Card

 

Graphics cards provide the link between computers and people by allowing us to read messages and information displayed on the computer screen. As with most other components of a computer, development of better graphics cards is proceeding fast. Recent models reach a higher level of performance, displaying more colors on-screen at faster and faster speeds. In the following section, you'll learn how to replace a graphics card in your computer and discover what you need to observe as you work.

 

An Illustrated Guideline The Graphics Card

 

 The S3 chip is one of the most common 32-bit graphics-chips and works as an accelerator for Windows. Its job is to optimize the screen display in Windows. The most recent version of this S3 chip addresses a video memory with a capacity of 4MB. Its maximum resolution is 1600 x 1200 pixels (or picture elements) with 256 colors. This chip provides true-color display at up to a screen resolution of 1024 x 768 pixels. Moreover, it is able to play back AVI-videos.

 

 The video memory that a graphics card requires is determined by the screen resolution and the color intensity that card can achieve. The video memory capacity necessary for a certain screen resolution can be determined easily by multiplying the column resolution by the line resolution. For example, when you have a 1024 x 768 pixel display, you need a minimum memory capacity of 786,432 bits. Then this sum must be multiplied once more by the color intensity (e.g., 8 bits in the case of 256 colors 786,432 x 8 = 6,291,456 bits). Since the video memory capacity is always expressed in KB, you now have to divide the previously calculated number first by 8 (8 bits are equivalent to 1 KB) and then again by 1024 (1024 bits are equivalent to 1 KB). In this case you will get a result of 768 KB, which means that a graphics card with a video memory capacity of 1 MB can display this resolution with 256 colors. The video memory can be extended either by DRAM (dynamic storage modules) or VRAM (video RAM modules). The latter are more expensive but build up the screen at a considerably higher speed.

 

 The feature connector facilitates the connection of the graphics card with other hardware components. Today it is often used to connect a graphics card to a video-overlay card (to digitize video sequences). In this situation, the video signal of the overlay card is linked up with the VGA signal.

 

 The graphics card BIOS works the same way as the BIOS of a computer: on the one hand, it contains important program routines (it acts in a way like an extension of the system BIOS), but on the other hand it is also responsible for the video memory control. Unlike the system BIOS, however, the graphics card BIOS is also responsible for generating the displayed character sets.

 

 A card with a VLB extension (Vesa Local Bus) only fits into a corresponding VLB slot and so is usable only in connection with special boards supporting the Vesa Local Bus.

 

 The VGA chip is responsible for the on-screen display in DOS. In addition to having a graphics processing chip especially constructed for Windows, cards like the S3 graphics card also have a VGA chip for on-screen displays in DOS or DOS programs.

 

AGP Card

 

AGP stands for Accelerated Graphics Port. It is a new interface specification developed by Intel Corporation. AGP is based on PCI, but is designed especially for the throughput demands of 3-D graphics. Rather than using the PCI bus for graphics data, AGP introduces a dedicated point-to-point channel so that the graphics controller can directly access main memory. The AGP channel is 32 bits wide and runs at 66 MHz. This translates into a total bandwidth of 266 MBps, double that of the PCI bandwidth of 133 MBps. AGP also supports two optional faster modes, with throughputs of 533 MBps and 1.07 GBps. In addition, AGP allows 3-D textures to be stored in main memory rather than video memory. This enables the card to utilize it’s own memory for processing the display output, resulting in faster video display. AGP has a couple of important system requirements. The chipset must support AGP and the motherboard must be equipped with an AGP bus slot or must have a built-in AGP graphics system.

 

There are several different levels of AGP compliance. The following features are considered optional but make life so much better, especially if you like to play the latest games:

 

Texturing: Also called Direct Memory Execute mode, allows textures to be stored in main memory.

Throughput: Various levels of throughput are offered: 1X is 266 MBps, 2X is 533 MBps; and 4X provides 1.07 GBps.

Sideband Addressing: Speeds up data transfers by sending command instructions in a separate, parallel channel.

Pipelining: Enables the graphics card to send several instructions together instead of sending one at a time.

 

Most of the direct support of AGP hardware under Windows 98 is handled internally by Windows 98 itself and is not accessible directly to programmers and end users. The AGP support is achieved through using the Microsoft DirectDraw API. So you should make sure that the AGP card you purchase supports DirectDraw.

 

Sound Card

 

The standard PC is generally only equipped with a small speaker for computer sounds. In the age of multimedia, a speaker with squeaky sound just doesn't do the trick. Newer PCs are sometimes already supplied with a sound card, which gives them better sound and music reproduction. If your PC doesn't have a sound card or you want to install a better card, this next section is perfect for you.

 

Types of Sound Cards

 

Sound cards are divided into three main groups, based on their performance:

 

8-bit sound cards: Although 8-bit-sound cards were state-of-the-art three years ago, they are practically on the scrap heap today. They can process sound data at 8 bits, which means that they can record and play back sounds with frequencies up to 44.1 KHz, but only in mono (as opposed to stereo). This is only really a problem if you want to do your own high-end multimedia work. The card is usually sufficient if you use it only for computer games.

 

16-bit sound cards: By doubling the data rate, a PC with a 16-bit sound card can provide sounds in stereo. While older 16-bit sound cards offer recording and playback at only 22.05 KHz (equivalent to the quality of a good VHF station), the more recent models already provide CD-quality stereo with up to 44.1 KHz.

 

Wavetable sound cards: Wavetable sound cards were developed out of work on 16-bit cards. Wavetable cards possess an additional wavetable-ROM chip and a digital signal processor (DSP). This ROM chip contains the digital sound equivalent of more than 100 musical instruments. This chip and the DSP, along with the corresponding software, facilitate a direct sound reproduction by stringing together samples in a way conventional sound cards can't accomplish. The card's performance is equivalent to a real concert hall experience, with up to 32 voices being simultaneously reproduced.

 

An Illustrated Guideline - The Sound Card

 

The CD-ROM interface serves as the contact for a CD-ROM drive already installed in the computer. By connecting the CD-ROM to the sound card, you spare the extra slot for the CD-ROM controller card, since the sound card takes care of controlling the CD-ROM. The gray ribbon cable of the CD-ROM needs to be connected to the plug on the sound card. Keep in mind that not every sound card works with every CD-ROM drive.

 

 After you connect the CD-ROM to the sound card via the CD-ROM interface, use the connection for the sound transmission. The 4-pin plug of the CD-ROM, which also needs to be connected to the sound card, is responsible for the sound transmission.

 

 The Wavetable-ROM, after which the new Wavetable cards are named, contains the digital sound equivalents of more than 100 musical instruments.

 

 The DSP chip (Digital Signal Processor) is able to take over certain sound card tasks or to produce certain emulations. For example, the DSP can make a sound card SoundBlaster-compatible. It is also able to convert a digitized sound into a general MIDI sound and is therefore important when producing samples.

 

 The synthesizer converts a digital sound from the sound card into the equivalent MIDI-sound.

 

 The D/A converter converts analog sound waves into digital sound so that the sound card can process them. It also re-converts the digital sound of the sound card into analog sound waves for the output. So, the D/A converter is at work when you digitize pieces of music coming from a tape recorder or text recorded via microphone with the help of your sound card. It is also at work when you retransmit those digital sound files through a speaker.

 

CD-ROM

 

If you want to make your PC multimedia-capable, installing a CD-ROM is essential. Because they have such large disk space requirements, most multimedia titles are packaged only on CD. Most newer PCs come with an installed CD-ROM drive as a standard. But CD-ROM drive technology advances rapidly (standard double-speed drives are already being replaced by triple- and even hextuple-speed drives), and you may want to install a better drive than the one you have. In this section, we will show you how to install a new CD-ROM drive in your PC and how to make the necessary settings.

CD-ROM Types and Standards

 

There are a number of CD-ROM drive specifications and standards you should know about before you make a purchase. CD-ROM drives are classified as single-, double-, triple-, and quadruple-, and hextuple-speed drives, according to their data throughput rate. There are also several standards referring to the form of the readable data. Here is a list of the most important terms:

 

-    Single-speed: Single-speed stands for a data transfer rate of 150 KB per second.

-    Double-speed: Double-speed stands for a data transfer rate of 300 KB per second. The higher data transfer rate is achieved through a higher rotation speed of the CD-ROM drives. The access time of these models is also faster.

-    Triple-speed: The data transfer rate of these models lies at 450 KB per second.

-    Quadruple-speed: This youngest generation of CD-ROM drives reaches data transfer rates of 600 KB per second with an access time of less than 200 milliseconds.

-    Hextuple-speed: CD-ROMs with data transfer rates of 900 KB per second.

 

-    XA standards: Your CD-ROM drive should be on this standard if you plan to use Kodak Photo CDs on your computer. XA stands for Extended Architecture, meaning that graphic and sound information may be located on the same track and that the CD may be recorded in several steps. (This is called being multisession-capable by the professionals.) For a photo-CD, this capacity is necessary, since regular photographic film usually allows only 36 shots, but up to 100 photos can be recorded on a CD.

-    MPC standard: For the MPC standard, developed by Microsoft, the drive must have a data transfer rate of 150 KB and an access time of less than 600 milliseconds, with a processor load of no more than 40%. Disk drives corresponding to this standard are able to process audio and data CDs as well as CDs containing both video and audio data.

-    White-Book: This is a the standard you'll need for playing back MPEG films and videos. To be able to read MPEG videos, the drive has to have higher performance than the XA standard. Specifically, under the white book standard, the third layer of the XA standard also has to be readable, while with the XA standard only the first two are being read. The following drives support the white book standard: Sony CDU-33A, Sony CDU-561, Philips CM-206, Philips CM-215, and Panasonic CR-562-B.

-    Green book: The green book standard comes from the interactive CD-I System by Philips, but it is also supported by the first computer CD-ROM drives such as the Sony CDU-33A and the Sony CDU-561.

 

-       SCSI CD-ROM drives: CD-ROM drives with an SCSI interface, such as those by NEC or Sony, constitute a special CD-ROM type. These have the advantage of better data throughput and, as an added benefit, you don't need an additional controller card in your computer if you already have a SCSI-controller. SCSI CD-ROMs are usually expensive, so it's really only worth buying one if you already own a SCSI host adapter.

 

DVD-ROM

 

DVD is short for Digital Versatile Disc or Digital Video Disc. It is a new type of optical CD-ROM that holds a minimum of 4.7GB (gigabytes) of information, enough for a full-length movie, and up to 17 GB. Many experts believe that DVD disks, called DVD-ROM’s, will eventually replace CD-ROMs, as well as VHS videocassettes and laser discs.

Do not confuse a DVD-ROM with a DVD-Video disc. A DVD-Video disc holds video and is played on a DVD player that you connect to your TV, similar to a VCR or laser disc. A DVD-ROM holds computer data and is read by the DVD-ROM drive in your computer. A DVD-ROM drive can read both DVD-ROM discs and DVD-Video disks, whereas a DVD-Video player can only read a DVD-Video disc. DVD-ROM drives are backward compatible with most other CD-ROM formats. They can read the variety of CD-ROM formats already available, including the standard audio CD-ROM.

The different capacity DVDs are referred to by their format. Below are the more common types available today and their differences:

DVD-5

About 133 minutes of video or 4.7 gigabytes of data

Information is recorded on one side only

The non-recorded side of the disk can be printed on

 

DVD-10

About 266 minutes of video or 9.4 gigabytes of data

Information is recorded on both sides of the disc

You must flip over the disc to read the other side

Printing is on the center ring only

 

DVD-9

About 240 minutes of video or 8.5 gigabytes of data

Information is recorded on both sides of the disc

You do not have to flip the over the disc to read this format

Printing is on the top side of the disc

 

 

A DVD-ROM offers:

Stunning video resolution and audio performance for multimedia and full-length motion pictures

Theatre quality five channel audio plus subwoofer channel

Image quality much better than standard VHS

Multiple CD titles, such as phone databases, map programs, encyclopedias, on a single disc

Developers of reference titles can use more video and audio clips

Game developers can create interactive games with full-motion video and surround-sound audio while adding more complexity to the game without running out of space.

 

To achieve the high-quality video, MPEG-2 compression is used to compress the video data. DVD drives are usually bundled in a kit with an MPEG-2 decoder board to assist in the displaying of the video.

A computer’s CPU can perform the calculations required, but not fast enough to process the audio and video, then have time to complete other tasks. These decoder boards decompress the video and send the audio and video data to the graphics and audio systems.

For the theatre quality sound, DVD movies use the Dolby AC-3 5.1 Surround Sound Audio specification. If your home entertainment system is equipped with Surround Sound, you can connect the AC-3 output from the decoder board to your home entertainment system.

 

The future of DVD looks promising as more variations come into the market.

DVD-RAM drives

Compatible with DVD-ROMS

Read/Write/Erasable

Storage capacity of 2.6 gigabytes per side great for backup and archival purposes

 

All in one decoder boards

Combine MPEG-2 decoding, Dolby Digital decoding and video and audio interface on one chip

Chip can be put on a video card, no need for separate video card and decoder board

Improved playback quality and performance

 

Hard Disk

 

Harddisk is the storage device used for the bigger programs and for main tasks such as multimedia and processing sheets etc, and is used for large softwares.

Hard Disk Types and Important Terms

 

Hard disks are divided into two main types: IDE disks and SCSI-disks. Both types come in a number of different models varying in storage capacity, access time, and data throughput rate. Which features you'll need will depend on how you plan to use your disk, but the hard disk type affects how you install the drive. With that in mind, we'll start off by explaining the difference between IDE and SCSI hard disks:

 

IDE disks: The IDE host adapter, which is equipped with 16 data lines, allows the attachment of two disk drives and of two hard disks at most. If you are installing a second fixed drive, you need to designate one drive as a "master" and one as a "slave" drive; you set that with jumpers on the drive. You'll want to configure the second hard disk (i.e., the one you are installing) as slave, because the hard disk from which the computer is booted has to be the master.

 

SCSI disks: Unlike IDE disks, of which you can have only two in your computer, you can have up to 7 drives (hard disks, scanners, CD-ROM drives, etc.), one behind the other, connected to your computer. The drives are connected with each other by a ribbon cable, which can't be longer than 6 meters. Each drive will receive an ID, a sort of house number so that it is clearly addressable, i.e., directable.

 

There also has to be a terminating resistor at both the beginning and the end of the line. These resistors are usually set by terminators, which look like miniature combs. Recent hard disks instead use terminating jumpers with the same function instead of the easily visible resistors. The SCSI host adapter should always be equipped with resistors, unless you are working with an external hard disk. At the other end of the line, the hard disk last attached to the cable should always be equipped with terminators.

 

The SCSI host adapter also has the ability to administer two disk drives by the means of a separate ribbon cable. A SCSI disk in general has higher data throughput rates than the conventional IDE disks, but it is also a little more expensive.

 

If any problems occur after the installation of a new SCSI drive, or if after booting the computer does not identify the new drive at the status signal of the SCSI host adapter, it could be that either the SCSI ID has been set up incorrectly or that the terminators have not yet been pulled out of the corresponding drive. Only the first and last devices on the SCSI chain should have terminators.

Main Memory

 

Main memory can be almost as scarce as hard disk storage, especially if you are working with Windows applications. In this section, you will learn how to extend your main memory in next to no time.

 

Memory modules called Dual Inline Memory Modules (DIMMs) were originally built for IBM PS/2 computers and do not fit into the plug-in units of conventional DIMMs. Today, they are also employed on the boards of other manufacturers, since they allow 32-bit access to the main memory.

 

The conventional DIMM packages expansion memory have different storage capacities, and are available with 32 MB, 64 MB, 128 MB, 256 MB, and 512 MB. Most motherboards have 2-3 slots for DIMMs. Some boards require that each slot be filled with a module of the same storage capacity.

 

Fax Modem Card (Internal Modem)

 

To communicate with other PCs, you'll need to install a fax modem card. This card allows you to send and receive documents, graphics, files, and programs. In this section, we'll show you the different modem types, how to install a fax modem card, and several important terms on telecommunication.

 

Modem Types and Important Terms

 

The Internet is a fast growing place. More and more people get connected each day and the technology rapidly changes. Gone are the days of plain text sites. Now there are fancy graphics, animations, audio and video. To view these new sites you need speed. In some cases even the fastest modems, 56K are not fast enough. The next option is a special high-speed 128K ISDN line, but those can be expensive. However, with Windows 98 you can install more than 1 modem and link them together, doubling your speed, and with two 56K modems, get near ISDN speed without the extra cost.

 

There are several different models of fax modem cards. Modems are generally classified by their data transfer rate, which is measured in bits per second. The regular modem rate is 2400 BPS and the high-speed modem rate is 28,800 BPS. The fax modem card offers an additional feature: it allows you to receive faxes on your computer that are sent from stand-alone fax machines. The faxes received in the computer can be printed out over the printer.

 

Further important terms on telecommunication:

 

8N1: This specification stands for your terminal program settings for transferring data. The 8 indicates the number of simultaneously transferred bits. (You can also use a 7N1.). The N stands No Parity, meaning the data will not be parity checked during the transfer. (Alternatively, you can use E for even.) The 1 defines the number of stop bits the terminal program should send.

 

Protocols: For the faultless transfer of files, you need a transfer protocol. This protocol guarantees that the transferred data arrived correctly at the remote station before it sends the next packet. The standard protocol today is the ZModem, but there are also fossils such as Kermit or XModem and various new developments like Compuserve-B, which governs data transfer at the online-service of the same name.

 

V.42bis Standard: A communications standard guaranteeing that two modems can compress and decompress data "on the fly," allowing better overall data throughput and guaranteeing error-free data transmission.

 

An Illustrated Guide: the Fax Modem Card

 

 The modulator/demodulator (modem) is a component you attach to your telephone. It converts information from analog into electric impulses and modulates them on the carrier frequency, in this case the telephone line. It also records arriving electric impulses and converts them into analog format.

 

 The A/D Converter, which you can find on sound cards, converts input analog information (in this case, the information of the modulator/demodulator component), into digital information (1s and 0s). This is necessary because the computer can only process digital information. The D/A converter also reconverts the digital information from the computer into analog information. It is the interpreter between the computer and the modulator/demodulator.

 

 Since the model shown here is a fax modem card, it has a special chip set on it, which controls the fax quality and the data rate. One common chip set is the Rockwell chip set.

 

Printer

 

There are four different printer types: dot matrix, ink jet printers, laser jet printers, and thermal transfer printers. Within these groups there are a variety of models differing in equipment, print quality, and cost. We'll give you a short description of the four different printer types and the printing methods involved.

 

Dot matrix printer: As the name indicates, the stylus printer works with steel pins. These pins, usually 24 of them, are located in a moving print head (it moves from right to left and backwards). The pins press on a ribbon, and wherever they press, ink is applied to the paper. The pens move because of an electromagnetic process. Since the print head only moves horizontally, the vertical movement results from the paper feed. Newer 24-pin printers usually achieve a printing resolution of 360 dpi; the older 9-stylus printers reach only 240 dpi.

 

Ink jet printers: Although ink jet printers and stylus printers both belong to the family of matrix printers, ink jet printers are much quieter than stylus printers. As with the stylus printer, this printer has a horizontally movable print head. The print head has nozzles instead of pins. The vertical movement for this kind of printer is also achieved by the paper feed. The print head sprays out ink by one two different methods: either via the thermic bubble method , in which ink is heated up until a gas bubble presses the ink lying in front of it out of the nozzles, or via the piezo-electric method, in which a crystal plate located in the opening of the nozzles contracts because of electric pressure and squirts out the ink. Ink jet printers usually reach a resolution of 300 dpi.

 

Laser jet printers: Laser jet printers employ a method very similar to photocopying. First, the whole page is built up in the printer memory. It is then printed in a manner similar to the way that copy machines work. Like copies, lasers use toner, a fine black powder. The printer applies the toner across the paper, and so that it will stick to the paper permanently, a high-temperature fixing unit sears the toner to the paper. Laser jet printers generally reach a printing resolution of 300 dpi, but 600 dpi (in PostScript laser jet printers) is becoming more and more common.

 

Thermal transfer printers: In thermal transfer printers, a special heated ribbon is pressed against the paper. The heated color comes off the ribbon like a coat of wax and covers the corresponding areas on the paper with color. The Star company offer this sort of thermal transfer printer (which reaches 300 dpi). This kind of mechanism works well for small color printers, but it isn't suitable for high-volume printers.

 

DirectX

 

Today’s programs utilize video, audio and high-end graphics to make their use easier or more enjoyable. These items can tax a system, but MMX technology coupled with DirectX commands helps to improve the processing of these items, resulting in faster usage.

 

MMX

 

MMX technology is actually new instructions added to the Intel family of processors that are specifically designed to handle video, audio and graphical data. MMX technology is built in to all Pentium II chips and regular Pentium chips that have the MMX logo. Windows 98 takes full advantage of the way that MMX streamlines instructions to your computer, resulting in faster, smoother, audio and video playback.

 

DirectX

 

DirectX is a group of application programming interfaces or API's that give developers direct access to your system's multimedia hardware, so that the speed and graphics of your multimedia applications are increased. DirectX emulates accelerator services when they are not present and lets you get the most out of the services that are available. Since DirectX is now an integral part of Windows 98, you will be able to run and display Windows applications containing a wider variety of multimedia elements such as video, full-color graphics, and 3-D animation.

 

DirectX is actually made up of several components.  Each contributes to the overall computing experience in different ways.

 

DirectDraw - a 2-D graphical interface that provides direct access to bitmaps in off-screen display memory, allowing for faster animations.

 

DirectSound - Allows applications to talk directly to your computer’s sound card to control mixing, playback and recording capabilities.

 

Direct3D - Supports 3D rendering capabilities built into many new video cards.

 

DirectPlay - allows games to be easily connected over a modem link.

 

DirectInput - Provides support for input from Joysticks, gamepads, keyboards, mice, Human Interface Devices and force feedback products.

 

DirectAnimation - Allows developers to build animations in layers, which can be controlled to produce multimedia effects.  These effects can be displayed in applications and through your web browser.

 

DirectShow - Provides support for DVD navigation, proxy filters, video and audio streaming, video mixing, and video and audio rendering.

 

What does all this mean for you?  Basically DirectX allows developers to provide more enhanced graphics and audio in today’s games and applications.  By using DirectX, developers can build one game that will work on all DirectX computer systems.