Nevertheless, there is a general rule of thumb. Ask yourself: “What am I going to do with
it?”
1.3.1DEPENDS ON USE
Most computer applications are categorized into five or six groups. The table, below,
shows the application, the associated computer setup name and the price range.
Table 2: Computer Categories and Prices
Application5 Examples Computer Category Price Range
Basic typing, database, email Basic/Middle $700-1200
Netsurfing web browsing/design, gen.
business
Middle/Advanced $1000-1500
Programming C/C++, Java, school Advanced $2000-3000
Multimedia/VR6 moving graphics, rendering Advanced/Advanced+ $2500-4500
Network Server service to other computers Server $3000-7000
1.3.2SYSTEM CONFIGURATIONS
When looking at system configurations (see table below), several things are “gimme's”
(typically part of the package). First, I promise that they will give you a keyboard! Other
things like a mouse, graphics card/monitor, power supply, case, etc., are part of the
package. Usually you don't have to worry about the number of watts the power-supply
offers or the kind of keyboard—unless you want something special.
The Server configuration may not look as “souped-up” as you might expect. Remember
that the server is not intended to assist the user directly: it is meant to serve other
computers on a network. You probably will not ever need a server for your home. I only
mention it here (along with the “minimum” configuration) for a point of reference.
Lastly, a real problem with creating something like this—it becomes out of date very
quickly. Please note that I wrote this in Sept. 1996. It became dated by Oct. 1996. (Yes,
I am serious!) This only for a guide; please scale accordingly or go ask someone: “I’d
like to buy a computer. What should I get?”
recommend getting a Computer Shopper Summary or Consumer Reports. Here’s another little trick: before
buying, call the support lines and just talk to them about they computer—ask them anything about it. If you
like them, buy it.
5 Please note: “applications” here mean “uses”. Whereas, in computer jargon, an “application” typically
refers to a large program like a word processor or spreadsheet.
6 VR (if you haven't been introduced to it through all the media-hype) stands for “Virtual Reality”. Virtual
Reality is an interactive three-dimensional view of the computer “world”. Typically it is used for games,
computer aided design (CAD), etc. If you want to experience VR, go to a computer store and ask them for
a demonstration (or try out any of the new games).
Table 3: Typical Computer Configurations, by Classification
Configuration CPU7 Cache Mem. HDrive Graphics Monitor CD-ROM Sound8 Modem Printer Tape
Minimum 386/ 25 - 4MB9 200MB VGA 512K 14” (yes) - - - -
Basic 486/ 100 256K 16MB10 1GB VGA 1MB 15” 4X 8bit 28.8K - -
Middle Pentium/
100
256K 16MB 1-2GB SVGA
2MB
15” 4-6X 16bit 28.8K Inkjet -
Advanced Pentium/
160
256K 32MB 2-3GB Ex.11 2MB 17” 8X 16bit
Wave12
33.6K Inkjet 1-4GB
Advanced+ Pentium/
200
512K 32MB 2-4GB Ex.2-4MB 17” 8X 32bit
Wave
33.6K/
ISDN
Laser 2-6GB
Server Pentium
Pro/200
512K 64MB 4-9GB SVGA 15-17” CD Tower
8X
- ISDN/
T1
Laser 2-
16GB
7 The first number refers to the processor “name” and the second number is the clock. For example 486/66 is a 80486 (compatible) processor at 66MHz.
8 A sound card configuration typically includes the speakers.
9 In order to run Win95, you need a minimum of 8MB of RAM.
10 You can get just 8MB of RAM, but Win95 will not run very well.
11 “Ex.” means SVGA Excellerator card.
12 “Wave” means “wavetable”. Sound cards with wavetables have the best sound when generating sounds like a piano, drum, etc.
1.4WHAT CAN I ADD LATER?
Jargon
Term Definition
CMOS RAM There are several parts of the computer’s memory which cannot be
forgotten and cannot be retrieved from the disk: these are stored in a
special battery-powered RAM, called CMOS RAM. CMOS is a special
type of chip processing that yields very low-power memory (et.al.). So a
battery can help retain CMOS RAM for several years.
The information stored in this memory is so critical that you cannot even
begin running (“boot-up”) the computer without it. A friend’s
computer’s battery died, and it took me about 3-4 hours before I got it
working again!
Connector A physical receptacle for data transfer. Usually has several pins or holes.
You will find either pins (male) or holes (female).
DMA “Direct Memory Access.” A special mechanism with the computer
hardware to speed up data transfer. When sending data to/from a disk,
the processor would have to stop all processing if it had to transmit each
byte. With DMA, the processor tells another controller to ship the data
for it. When the transfer is complete, the controller signals the processor
that it is ready for another transfer request.
IRQ “Interrupt ReQuest.” The programs run on their merry way until
something happens externally. For example, when you type something
or move the mouse, the controllers which handle those interactions will
signal the processor indicating that data is waiting to be picked up. Each
device is assigned an IRQ number.
I RQ D evice
0 Timer
1 Keyboard
2 (special—never use!)
3 COM2, COM4
4 COM1, COM3
5 -
6 Floppy (on newer computers)
7 (parallel port, may be shared)
8 System CMOS, Realtime clock
9 -
10 -
11 -
12 -
13 Numeric data processor
14 IDE Controller
15 IDE Controller (newer computers with EIDE)
Through a glitch in most operating systems on the PC, no two devices
can share an IRQ number.
Jargon
Memory
Address
Think of a microprocessor like a “master indexer” and the memory as
the index. Every byte of memory is assigned a numeric index. The
microprocessor sends a memory address (an index number) and then
waits for the data. The memory chips receive the address and send the
data. The delay between sending and receiving will play an integral part
in your computer’s performance.
Within the last few years, processors request data much faster than the
RAM can respond.13 So, fast caches were introduced. Caches grab the
data in blocks so that 95% (or better) of memory accesses are found in
the cache.
Port A port is a connector usually in the back of the computer. There are
several ports through which the computer interacts with the outside or
the user. Some ports include: keyboard, monitor, serial, parallel,
telephone, etc.
Port Address Every device that is connected to the computer has to send and/or receive
data through a special part of the computer memory called a “port”. Port
addresses (because they are connected to devices) are very sensitive—
even looking at the data may change the device. So ports are not in the
same address space as regular computer memory.
It is very important to understand that no two devices can share port
addresses—ever! For example, if you have a problem getting your
network card and mouse to work together (when you take out the
network card, the mouse begins functioning again), you likely have a
port conflict. Usually, devices can be configured to have different
addresses: simply turn off the computer and select a different address.
“Plug & Play” is supposed to configure your ports and interrupts for you.
After a while, you probably will want to add various options or replace some components
to bring your machine more up to date. Let's face it: we all like toys! Computers are big,
expensive, useful toys. Keep in mind that unless you have a lot of experience with
playing with the computer components, you probably don't want to open your computer.
Beware, all bare components are very sensitive to static electricity—even imperceivable
zaps can nuke memory, processor or cards. Be very careful.
13 A little math: a 200 MHz Pentium typically uses 60ns RAM. If the processor were to request data as
quickly as it uses it (assuming one data access per clock tick), faster than 5ns RAMs would be needed.
That’s 12x faster than the typically configured system! The reason faster RAM is not used is because very
fast RAM is VERY EXPENSIVE.
That behind us, let's look at what we can do. I have separated the upgrades by difficulty
and have included suggestions as to where to get your new equipment.
1.4.1EASY UPGRADES
Those things that are easy to add are
essentially connected via a cable. If
you have the spare port or you want
to replace a keyboard, all you have
to do is plug in the new printer,
monitor, etc. Most computers have
keyboards and monitors, so buying
a new one will obviously mean
disconnecting the old and plugging
in the new.
Some of the things you can add or replace are 1) printer(s), 2) external modem, 3)
keyboard, 4) serial mouse and 5) monitor. If you want to add a printer or external
modem, you will have to make sure that you have a spare port. Look on the back of the
computer: if you see a 25-pin female connector (you don't see pins) that is likely a parallel
port to which you can connect a printer. A serial port is a nine- or 25-pin male (you can
see the metal pins) connector. Most modems do not work on nine-pin serial ports; and
most serial mice prefer nine-pin serial ports. If you need to get more ports see the More
Difficult section, below, for installing I/O boards.
When adding an external modem or printer, you will likely have to buy a cable as well.
Ask the salesman if you need one. Lastly, after plugging-in the new printer, modem or
monitor, you will have to “tell” Windows 95 that there is new hardware. Refer to the
“Setting-up printer/modem/monitor“ (page 59) on how to do this.
Advanced:
When working with ESD (Electrostatically-Sensitive Device), make sure you are well
grounded. Here are a few tips to ensure proper grounding:
1. Get a grounding strap (you can get them from most electronics shops for $5-$10)
and connect it to the chassis of the computer.
2. If you are standing on a rug, take off your shoes and either walk around bare-foot
or in stockings (this may sound funny—but it works!).
3. Before you touch any ESD, touch a grounding point: (if the computer is still
plugged-in—not a good idea) the computer chassis, the screw on a light switch or
outlet, or a cold water pipe.
4. Make sure that ESDs are shipped or carried in antistatic containers (all businesses
will do this for you). If you are carrying some ESDs, you can make-shift an
antistatic container by wrapping the parts in aluminum foil.
Figure 1: 25-pin Serial Port
Figure 2: Parallel & 9-pin Serial Ports
1.4.2DIFFICULT UPGRADES (ADVANCED)
The next level of difficulty requires opening the computer. What is more difficult is 1)
being careful that nothing gets “fried”, 2) configuring the new card, and 3) sometimes
rearranging other cards' positions and/or configuration. Anytime you need to open your
computer and move around or add cards or memory, be very, very careful. It takes very
little effort to “burn” with static electricity the component you’re touching. Start by
unplugging the computer. If you have any apprehension, hire someone to reconfigure
your computer.
Windows 95 has made some of this easier with “Plug & Play”. With Plug & Play
compatible cards (which most are not), you simply should be able to plug in the card and
let Windows 95 decide how to configure it. Unfortunately, you can’t always count on
this. However, if the hardware is configured correctly, Windows 95 will automatically
detect (unlike adding an external printer, modem or monitor) and reconfigure itself.
Some of the things you can add are: scanner, internal modem, new VGA card, RAM,
“Overdrive” CPU, I/O cards, and CD-ROM drive. Adding RAM or adding an Overdrive
CPU requires no additional configuration. Likewise, replacing (you can't have more than
one) the VGA card is as simple as 1) unplugging the monitor and computer (both the
cable between the computer and monitor and their power), 2) opening the computer, 3)
removing the old VGA card, 4) plugging in the new, 5) closing the computer housing,
and 6) plugging in the computer and monitor.
First make sure that your Hardware Configuration List is up to date (see page 62). You
will use it to select the available port address, DMA and IRQ. Read thoroughly the
installation instructions that come with the new card. Find out what the card needs in
order to be properly configured. See the table, below for likely needs and configurations:
Table 4: Component Configuration
Component Needs Likely Configuration
Scanner14 I/O Port, DMA, IRQ I/O Port = [Depends on manufacturer]
DMA=2-7
IRQ=2-15
Modem I/O Port, IRQ I/O
Com1
Com2
Com3
Com4
Port
3F8
378
2F8
278
IRQ
4
3/5
4
3/5
Sound Card I/O Port, IRQ, DMA
I/O Cards I/O Port, IRQ [, DMA] (Follow included instructions)
CD-ROM I/O Port, IRQ, DMA
14 Please note that Windows 95 has had no end of problems with scanners. Make sure that when (and if)
you get one it is 100% compatible with Windows 95. Then install it as soon as you get home and try it out.
One of the problems I have observed is that it may work the first time, but after turning off then on the
computer, the scanner no longer works. Lastly, get a very reputable brandname.
1.4.3MOST DIFFICULT UPDATES (EXPERT)
The most difficult reconfigurations require changing a lot more than the card or
component you're adding. Some of these things are about as complex as “Difficult
Upgrades (Advanced)“ (page 26) section in terms of adding the hardware, but you may
have to install special hardware drivers to use the new hardware. Even some hardware
requires you to change the CMOS, a critical piece of memory that allows you to run your
computer. An overview of instructions can be found in the table, below.
Table 5: More Difficult Hardware Configurations
Component How to install
Harddrive To replace a harddrive, you should backup all private information onto
floppies (or tape). Usually you will not need to backup the program
applications (e.g. Windows, Word, etc.) because you should have
original disks for those. However, if you have the time and floppies, go
ahead and backup everything. Also you must have a floppy from which
you can boot to install Windows again.
Reboot computer. When the computer displays anything about changing
BIOS or CMOS, press the appropriate keys (typically, <DEL>,<ESC> or
<F1>). Go into basic computer configuration (or wherever the harddisk
information is—you may have to search around a bit) and copy down the
numbers associated with your current drive (Heads, Cylinders, Sectors,
etc.) onto a piece of tape which you will stick to your old drive.
Turn off computer and open. Remove old drive and plug in new one.
Turn on computer and go back into CMOS configuration. Using the
numbers supplied by the manufacturer of the new drive, replace the old
numbers. Exit and save new CMOS settings. Some computers have an
“auto-harddrive detection”, use that instead.
Reboot the computer with the Windows 95 installation floppy in the A:
drive. The computer should ask you if you want to partition your drive.
Reply 'yes'. Follow the directions from there.
Note: If you have an old controller card (pre-1994), you will likely have
to replace this as well in order to use new drives with capacities greater
than 540MB. They may fix the problem that an old motherboard has
with reading these large drives. If it doesn't work, after following
directions, take it back immediately.
Component How to install
Second
Harddrive
If you want to add a second harddrive, you must have setup
documentation of your primary drive. From this documentation, you
need to know how to make it a master drive. The new, secondary drive
will be the slave drive. The new harddrive will have with its
documentation information on how to make it a slave.
After configuring the two drives, connect the new slave drive to the same
ribbon cable as the master—use the middle plaster connector. Connect
power to drive and turn on computer.
When the CMOS configuration appears, press the keys needed to enter
configuration. If your menu includes an “auto harddrive detection”,
select that and save and exit. Otherwise, go to the section where the
harddrive configuration is and change the second drive to read Type #47
and set the other numbers as defined in the documentation. Save and
exit.
Reboot computer. Partition the new disk and format.
Motherboard Turn on computer and go into CMOS configuration. Copy down
harddrives numbers. Turn off and unplug.
Open your computer and remove all the cards. You may have to remove
the harddrives as well. Remove other cables (like keyboard, speaker,
reset, LEDs, etc.). Disconnect the motherboard from power—this is hard
to do, be patient and squeeze the connectors with your fingers. Remove
the motherboard's mounting posts (either plastic or metal). Remove old
motherboard.
Move or install your RAM into the new motherboard.
Insert new motherboard (and hope that the mounting posts and slots line
up—often they don't). Connect posts, power, display card and monitor.
Turn on computer just long enough to verify that the new motherboard
works (you should get lots of errors). Turn off. Reconnect and replace
all the cards.
Turn on. Go into CMOS configuration and either select auto harddrive
detection or manually add the harddrive configuration that you had
copied down. Save. Reboot.
Component How to install
Processor If you have a “ZIFF” socket on your motherboard (it will have a lever
which will easily release the processor, replacing the old with the new
one is very easy. There are a few things you need to keep in mind:
11. Some processors use a different voltage—make sure you get the right
one.
12. Make sure that the new processor is “pin-compatible” with the older
version.
13. If you are plugging in a microprocessor “module” (a board with the
processor on it), you may have problems with the ZIFF lever.
14. You may have to change some of the RAM timings found in CMOS.
Ethernet
Card
The ethernet card usually installs with no more difficulty than installing a
sound card. However, some have RAM on the card. Follow the
directions for installation.
SCSI
Devices
SCSI is very nice for adding new drives and improved performance. A
SCSI uses a “daisy-chain” interconnection of components—the computer
is connected to the disk, the disk is connected to a scanner, and the
scanner is connected to another disk. However, not only do you have to
worry about the Port address, DMA and IRQ, you will have to be aware
of SCSI IDs.
There are eight “available” IDs on a typical SCSI. However, two
numbers are special: zero (boot device—always a disk) and seven (card
device). You can have all the devices on any other ID.
1.4.4HARDWARE SOURCES
The next big question is where do I get new hardware? There are many, many sources
you can pursue; they all fall into four groups: mail-order, original supplier, retail and
used.
Table 6: Hardware Sources
Source Advantages Disadvantages
Mail Order · Cheapist
· Tons of sources
· “Easy” returns
· Delivery within 2-3 days
· Get recommendations (lots of
“bad apples”)
· Can’t see/read about the product
· Doesn’t know your computer or
its configuration
· You’re on your own
· Returns often charged 10-15%
restocking fee
· Tricky business of interstate
commerce