User:Rewood/Brief Guide to Computer Specifications
About Hardware Specifications
CD-ROM vs. CD-RW vs. DVD vs. DVD-R/W
All new computers typically come with a CD-ROM drive, which can read both data CDs and conventional music CDs. These drives are usually rated by their rotational speed as compared with that of a standard audio CD player. A 24x CD-ROM drive theoretically rotates 24 times as fast as a standard audio CD drive, making it possible to read data from the drive much more quickly. However, any rating higher than 24x will give only minimal improvement in performance over the entire surface of the data CD.
Some computer manufacturers now choose to substitute a DVD-ROM drive for a CD-ROM drive. A DVD drive can play back
- Data CDs
- Audio CDs
- DVD-ROM titles
- DVD movies (if additional hardware and/or software is installed).
DVD drives, like their CD counterparts, are usually rated by their rotational speed, and 16x is considered current.
Many new computers offer a CD-RW drive or even a combination DVD/CD-RW drive. This type can read both data and audio CDs and, when used with authoring software and special media, can write data and audio CDs. These media are available in two forms:
- Write once (CD-R) is usually preferable because it can be easily read on standard CD-ROM drives and most audio CD players.
- Write many (CD-RW) or re-writable media, as the name implies, can be recorded and re-recorded multiple times.
Some re-writable CDs can not be played back in regular CD-ROM drives. CD-RW drives usually have multiple speed designations, which can be a little confusing. For instance, a drive designated as "8x4x32x"
- can write a CD-R in 1/8 the time of a standard 1x drive (9.25 minutes vs. 74 minutes for a full CD).
- can write a CD-RW in 1/4 the time.
- is a 32x rated CD-ROM drive.
CD-RW drives have become increasingly popular to use for backing up your hard drive.
While Zip Drives can now store up to 750 MB of data, CD-Rs typically can store 640 MB on very inexpensive media that can be read with a conventional computer CD drive. We encourage those buying new computers to seriously consider purchasing a CD-RW as a part of their system.
If you choose to purchase a CD-RW, we recommend that you have an additional CD or DVD drive to make it easier to duplicate CDs without having to copy the information from a CD to the hard drive and onto a CD-R or CD-RW.
Finally, recordable DVD drives are quite common these days. These drives are useful for large data storage needs since they can store up to 4.7GB of information, as well as for recording conventional DVD Video disks.
Most DVD-RW drives will also write to CD-R and CD-RW media, as well as being able to play back all common removable optical formats (DVD, CD, CD Audio, etc). Shopping for DVD-RW drives can be a little confusing, as there are more than one media type available.
In brief, there is:
- DVD-R/RW -- can use both DVD-R (write once) and DVD-RW (re-writable) media
- DVD+R/RW -- can use both DVD+R (write once) and DVD+RW (re-writable) media
- DVD-R/RAM -- can use both DVD-R (write once) and DVD-RAM (re-writable) media
All of Apple's line can be ordered with a "SuperDrive", which is a DVD-R/RW drive. Dell, Hewlett-Packard and others use DVD+R/RW drives. All work about the same, and can create DVD's that will play back on each other's DVD drives, as well as DVD Video players, when combined with DVD authoring software. How much RAM is enough? Random access memory (RAM) is used by the computer to execute applications and store data temporarily. Computers tend to run better and more reliably when they are outfitted with sufficient RAM.
Given the dramatic drop in memory prices, it makes good sense to begin with 512MB of RAM on a machine that will be running Windows 2000, XP or MacOS X, and it is not unreasonable to have 1 GB. Indeed, some specialized applications may perform significantly better with this much RAM. Check to see if your department has its own recommendations on minimum RAM.
If you are using an older computer running Windows 98/98SE or Millenium Edition (we don't recommend WinME), 256 MB is considered optimal. Because of limitations of the operating system, additional memory is not necessarily used effectively. When either upgrading or buying a new system, pay special attention to:
- The number of free memory slots in the computer. Some inexpensive ones will have only two slots with one already filled, limiting your options to upgrade the memory.
- The correct memory type for your machine.
Some computers may have special requirements. Do I need a Zip drive? Zip drives are removable media drives made by Iomega Corporation. They require special disks that can be used only in a Zip drive but hold much more data than a standard floppy. They are available in both internal and external models and in three capacity sizes:
- A 100 MB drive is much more common but can read and write only 100 MB disks.
- A 250 MB drive can read and write both 250 and 100 MB disks and may be a better option for a new computer.
- A 750 MB drive can read all previous formats, and will write 750 and 250 MB disks.
Many Unity lab machines are outfitted with a Zip drive, offering a very convenient way to transport projects and data from your personal computer to a lab machine. It is certainly not required, but its low cost may make it an attractive accessory. What about USB and Firewire? USB is an interface standard for computer peripheral devices. The original USB standard is
- designed for low cost and ease of use
- standard on all new Macintoshes and virtually all new PC's
- supported on the PC only under Windows 98, ME, 2000 and XP
- commonly used on mice, printers, keyboards and image scanners, where it works quite well.
A newer USB 2.0 standard has been released and is becoming commonplace. USB 2.0 is
- more effective for exernal file storage devices and CD recorders since it can transfer data at much faster rates than the original USB standard
- supported by Microsoft only under Windows XP and Windows 2000.
Support will not be provided for Win98/ME, nor does Apple plan to provide support for USB 2.0 in its operating systems.
Firewire is a high speed interface that is
- available on all new Apple models and an increasing number of PC models
- known under the Sony brand name iLink and its generic designation IEEE-1394
- commonly used to interface digital video equipment to a personal computer
- used also for devices such as CD-recorders, external hard drives and image scanners
- expressly designed for high throughput situations while offering simple connectivity similar to USB
- best supported on the PC under Windows 98/SE/ME, 2000 and XP.
However: with Windows 2000 and XP, Microsoft ships native support for some Firewire interface cards. with Windows 98 and Windows ME, the computer or device manufacturer must supply driver support for Firewire.
Selecting a monitor
Monitor prices have come down dramatically recently, and as a result, larger monitors are now priced in a readily affordable range. Larger monitors allow bigger desktop sizes, which can significantly aid in productivity, particularly when using graphics packages.
- A 17" monitor can easily display a 1024x768 (known as XGA) desktop.
- A 19" or 21" monitor can display a 1280x1024 (SXGA) desktop at a very comfortable size, but a 21" monitor requires a significant amount of space, perhaps more than a residence hall room desk can provide.
When shopping for a a CRT (picture tube based) monitor, pay attention to the * Screen size. This is measured diagonally and is often not the actual viewing size. By law, manufacturers must list both the normally quoted size and the actual viewing area of a monitor. A 17" display may have only a 15.8" display area.
- Dot pitch. Smaller is better.
- Type of picture tube used.
The latest innovation is the flat face display (not be confused with a LCD display), which greatly reduces glare, making the display easier on the eyes, especially over long periods of time.
LCD displays are easily spotted by their svelte profile. They are much thinner and lighter than traditional displays, making them attractive for those with limited desk space.LCD displays typically generate less heat, and use less electricity.
Unlike CRT displays, LCD display sizes are typically accurate (e.g., a 15" display actually offers 15" of viewable area), but they are more expensive -- about twice the cost of conventional displays. Despite their higher cost, they are becoming increasingly popular. When shopping for LCD displays, in addition to dot pitch, pay attention to contrast ratio values (ratio of darkest to lightest pixels). 300:1 is considered decent, 500:1 is close to state of the art. In addition, it is important to match up the display resolution with your preferred desktop size.
Unlike conventional CRT displays, LCD displays have optimal resolution values. For 15" displays, it is typically 1024x768. While these displays will operate at higher and lower resolutions, image quality may be compromised slightly.
Selecting a display card
A display card is an internal device that converts digital content into something that can be displayed by a monitor. Key features to look for when either shopping for a new computer or upgrading an older one are
- The type of computer interface the card uses. You must purchase a display card that has software support for your specific computer. New display cards use one of two types of internal interfaces: o PCI is an older standard that is supported on both Macintoshes and PCs built since 1986. o AGP is a newer, higher performance interface that has appeared on the newest generation of Macintoshes and is commonly available on new PC systems as well.
- The amount of RAM on the card. This determines the size of the desktop that can be displayed on a given monitor. For a 1024x768 display supporting 24 bit (16.8 million) color displays, 8 MB of video RAM (VRAM) is more than enough. For larger monitor sizes, the card may need more memory.
Fortunately, the majority of new display cards have at least 8 MB, and it is quite common to see them with 32 MB. VRAM also impacts the performance of the display card, particularly for applications that use 3D graphics, such as games. For this reason, many high performance cards may come with 32 MB or more of VRAM
- Whether the card supports hardware-based 3D acceleration. This can be a little confusing for new consumers. It's recommended that potential buyers determine the type of 3D acceleration (for example, OpenGL) required by their software before buying a new display card. For many games, requirements are printed right on the box.
- What kind of display connector the card has. The most common interface is the standard VGA connector that the majority of monitors support. DVI (Digital Video Interface) is a newer standard that is designed for use with many (but not all) LCD displays. DVI can offer sharper images and text, but both the display and graphics card have to support it. Apple's products use either standard VGA or a variant of the DVI interface, known as ADC (Apple Digital Connector), To use a non-Apple DVI display with these machines, an adapter has to be purchased.
Facts about hard drives
A 20 GB drive will likely be the the smallest one available on a new computer. Doubling that capacity may cost only a small percentage more. However, certain computer activities (e.g., editing digital video) may require much more drive space. For users of multimedia applications, 80 GB may be a more appropriate starting size.
The drive interface most commonly used now on both the Macintosh and the PC is a high speed variant of the intelligent device expansion (IDE) interface that has been in use for at least 10 years. This modern interface is known as UDMA IDE. Newer drives, combined with higher speed controllers, can transfer data fast enough for the most demanding tasks, including digital video. A hard drive rotational speed of 5,400 rpm is considered pedestrian, 7,200 rpm is considered medium to high performance and 10,000 rpm is close to state-of-the-art.
Drive performance is too difficult an issue to attribute to just one number, but suffice it to say that most current drives are quite fast. Small computer systems interface (SCSI) is another drive interface. It was prevalent on Macintosh computers until the introduction of the G3 Blue and White tower systems and was used on PC based systems as a high performance alternative to the slower (at the time) IDE interface.
SCSI is still used for peripheral devices such as Zip drives and scanners and for high-end applications where cost is secondary to performance. SCSI mass storage devices tend to cost more than their IDE counterparts. When adding a drive to an older machine, keep in mind that:
- Many older machines have limits on the size of a usable hard drive. To address this problem: See if drive preparation software, which may be bundled with the drive, might help circumvent the limit. Upgrade the system's BIOS (the computer's firmware that handles low level tasks) if possible.
- IDE interfaces can support only two devices simultaneously. Some older machines may have only one IDE interface, and that may already be supporting the CD-ROM and hard drive.
What about wireless networking?
NC State University is providing wireless access to the network in an increasing number of locations, however, it is by no means ubiquitous. Currently, NC State supports the 802.11b, or Wi-Fi, standard for wireless access. This is the same standard supported by Apple's Airport access points and many other vendors' products.
Individuals interested in using wireless access should:
- Check to see if their department supports it and recommends a specific brand of wireless card. (Generally, ComTech recommends Orinoco or Cisco Aironet 802.11b adapters.)
- Ask a departmental support person or an Information Technology Division consultant before purchasing the equipment.
- Be aware that once NC State provides wireless service in a building, it is a violation of policy to have other personal or departmental wireless access points in that building.
- Check the list of places on campus where wireless is available. (New locations will be added throughout the year.)