Principles of computer design

1

Principles

of

Computer

Design

2

Contents Computer Architecture ........................ 5

Von Neumann Architecture .......... 5

Intel CPU Microarchitectures............... 9

RISC and CISC Instruction Set ............. 10

RISC .............................................. 10

Typical RISC Architecture Based

Machine – Instruction Phase

Overlapping ................................. 12

Advanced RISC Machine .............. 13

CISC .............................................. 14

Typical CISC Architecture – Stack

Design .......................................... 15

RISC and CISC in Comparison ...... 16

CPU Benchmark ................................. 17

CPU .................................................... 19

Components of the CPU .............. 21

Motherboard ..................................... 24

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ASUS P5AD2-E Premium

Motherboard ............................... 26

RAM ................................................... 29

VGA ........Error! Bookmark not defined.

ROM ................................................... 34

HDD .................................................... 36

Hard disk drive components ....... 37

SSD ............................................... 39

MULTITASKING .................................. 40

Advantages of multitasking ......... 41

Disadvantages of multitasking .... 41

MULTIPROCESSING ............................ 42

MULTITHREADING ............................. 44

CPU Core Structure ............................ 47

Single Core ................................... 47

Dual-core ..................................... 48

Multi-core .................................... 50

4

Nanotechnology CPU Design ............. 51

Cache Memory ................................... 53

L1 and L2 Caches ......................... 54

Smart Caching ............................. 55

BIOS .................................................... 56

The four main functions of a PC

BIOS ............................................. 57

Windows Registry .............................. 60

Registry Root Keys (hive name) ... 62

Windows Registry values ............ 64

Protect Computer from Threat .......... 66

Ergonomic rules ................................. 69

Computer Ergonomics - Working

Positions ...................................... 70

Computer Ergonomics - Placement

of Components ............................ 71

5

Computer Architecture

Von Neumann Architecture

It is the first written description of how an

electronic computer should store and

processes information.

Von Neumann architecture was originally

published in John von Neumann's report of the

EDVAC on June 30, 1945.

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This architecture is consist of:

an Arithmetic Logic Unit (ALU)

memory

Input/output

a control unit

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Von Neumann computers have some

drawbacks.

They carry out instructions one after

another, in a single linear sequence

They spend a lot of time moving data

to and from the memory.

This slows the computer and as an instruction

fetch and a data operation cannot occur at the

same time because they share a common bus;

this problem is called as the von Neumann

bottleneck.

One way to avoid the von Neumann

bottleneck is to build the computer so it

performs operations in parallel (so-called

parallel processing).

Another common trick is to separate the bus

into two or more busses, one for instructions,

another for data.

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But such modifications don't really amount to

much more than variations of the original

architecture.

This design is still used, in one form or

another, in all computers and many electronic

devices produced today.

9

Intel CPU Microarchitectures

10

RISC and CISC Instruction Set

RISC

Reduced Instruction Set Computer (RISC)

is a type of microprocessor architecture that

utilizes a small, highly-optimized set of

instructions.

The first RISC projects came from IBM,

Stanford, and UC-Berkeley in the late 70s

and early 80s.

The IBM 801, Stanford 3 [RISC AND CISC]

MIPS, and Berkeley RISC 1 and 2 were all

designed with a similar philosophy which has

become known as RISC.

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Some design feature characteristics of RISC

processors:

One cycle execution time: RISC

processors have a CPI (clock per instruction)

of one cycle. This is due to the optimization of

each instruction on the CPU and a technique

called;

Pipelining: a technique that allows for

simultaneous execution of parts, or stages, of

instructions to more efficiently process

instructions;

Large number of registers: the RISC

design philosophy generally incorporates a

larger number of registers to prevent in large

amounts of interactions with memory

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Typical RISC Architecture Based Machine –

Instruction Phase Overlapping

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Advanced RISC Machine

14

CISC

Complex Instruction Set Computer or

Computing is a type of microprocessor design

which refers to computers designed with a full

set of computer instructions that were intended

to provide needed capabilities in the most

efficient way.

CISC architecture contains a large set of

computer instructions that range from very

simple to very complex and specialized but by

reducing the full set to only the most frequently

used instructions, the computer would get more

work done in a shorter amount of time for most

applications (RISC).

Examples of CISC Processors are:

Motorola 680x0 family

Intel 80186 through Intel 486 &

Pentium.

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Typical CISC Architecture – Stack Design

16

RISC and CISC in Comparison

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CPU Benchmark

CPU benchmarking is a type of measurement

for computer performance. It is applied to the

central processing unit, or CPU, of the

computer system.

These measurements help observers to

understand standards for computer

functionality. Moreover, they provide a set of

standards that allow users to compare the

performance of different machines under the

same circumstances.

CPU benchmarking increases speed and

capacity or capability.

The observers will often assess the clock rate,

which is the rate that the CPU can process

commands. Other types of processor function

may also be assessed. The benchmark will

provide the core standard for the design of a

CPU, or simply be recorded in quality or

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production research. The final outcome

involves much more testing and trials of

developed prototypes.

The software that helps to determine

benchmarks must be matched with specific

operating systems.

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CPU

CPU is the Central Processing Unit of the

computer which also known as a processor,

central processor, or microprocessor.

It handles all instructions it receives

from hardware and software running on the

computer.

The CPU was first developed at Intel with the

help of Ted Hoff and others in the early 1970's.

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The first processor released by Intel was

the4004 processor.

The processor is placed and secured into a

compatible CPU socket found on the

motherboard. Processors produce heat, so

they are covered with a heat sink to keep them

cool and running smoothly.

The CPU chip is usually in the shape of a

square or rectangle and has one notched corner

to help place the chip properly into the CPU

socket. On the bottom of the chip are hundreds

of connector pins that plug into each of the

corresponding holes in the socket.

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Components of the CPU

The primary components of the CPU are:

ALU (Arithmetic Logic Unit) -

performs mathematical, logical, and

decision operations

CU (Control Unit) - directs all of the

processors operations

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There are several types of processors. The

AMD Opteron series and Intel Itanium

and Xeon series are CPUs used in servers and

high-end workstation computers.

Some mobile devices, like smartphones and

tablets, use ARM CPUs. These CPUs are

smaller in size, require less power, and generate

less heat.

AMD Processors:

K6-2

K6-III

Athlon

Duron

Athlon XP

Sempron

Athlon 64

Mobile Athlon 64

Athlon XP-M

Athlon 64 FX

Turion 64

Athlon 64 X2

Turion 64 X2

Phenom FX

Phenom X4

Phenom X3

Athlon 6-series

Athlon 4-series

Athlon X2

Phenom II

Athlon II

E2 series

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A4 series

A6 series

A8 series

A10 series

Intel Processors:

4004

8080

8086

8087

8088

80286 (286)

80386 (386)

80486 (486)

Pentium

Pentium w/MMX

Pentium Pro

Pentium II

Celeron

Pentium III

Pentium M

Celeron M

Pentium 4

Mobile Pentium

4-M

Pentium D

Pentium Extreme

Edition

Core Duo

Core 2 Duo

Core i3

Core i5

Core i7

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Motherboard

Alternatively referred to as the mb, mainboard,

mobo, mobd, backplane board, base board,

main circuit board, planar board, system board,

or a logic board on Apple computers.

The first motherboard is considered to be one

used in the IBM Personal Computer, released

in 1981. At the time, IBM referred to it as a

"planar" instead of a motherboard.

The motherboard is a printed circuit board that

is the foundation of a computer, located on the

back side or at the bottom of the computer case.

It allocates power to the CPU, RAM, and all

other computer hardware components.

Most importantly, the motherboard allows

hardware components to communicate with

one another.

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The computer components included in the

motherboard are:

The microprocessor

(Optionally) coprocessors

Memory

basic input/output system (BIOS)

Expansion slot

Interconnecting circuitry

Additional components can be added to a

motherboard through its expansion slot.

The electronic interface between the

motherboard and the smaller boards or cards in

the expansion slots is called the bus.

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ASUS P5AD2-E Premium Motherboard

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There are several motherboard brands in the

world.

Gigabyte

Gigabyte may very well

be the best motherboard

brand out there.

Gigabyte motherboards have received

consistent, above average to high ratings from

all major computer supply sites.

EVGA

EVGA is a computer

parts manufacturer that

focuses mainly on

motherboards and graphics cards. Like Asus

and Gigabyte, EVGA is another company that

has received some great reviews from

consumers.

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Intel

Intel has the least variety for

motherboards, and selection is

limited. However, their

motherboards are top quality,

and receive positive reviews from customers

the majority of the time.

Asus

Asus currently distribute

motherboards, graphics

cards, computer monitors and even their own

brand of PCs. Unlike other PC manufacturers

like Dell, HP, and Gateway, Asus sells their

motherboards on sites like Newegg and Tiger

Direct, so that computer builders and

gamers can purchase just the motherboard at an

affordable price.

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RAM

Random Access Memory, a type of computer

memory that can be accessed randomly; that is,

any byte of memory can be accessed without

touching the preceding bytes. RAM is the most

common type of memory found in computers

and other devices, such as printers.

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There are two main types of RAM.

DRAM (Dynamic Random Access

Memory)

SRAM (Static Random Access

Memory).

The two types of RAM differ in the technology

they use to hold data, with DRAM being the

more common type. In terms of speed, SRAM

is faster. DRAM needs to be refreshed

thousands of times per second while SRAM

does not need to be refreshed, which is what

makes it faster than DRAM.

DRAM supports access times of about 60

nanoseconds, SRAM can give access times as

low as 10 nanoseconds. Despite SRAM being

faster, it's not as commonly used as DRAM

because it's more expensive. Both types of

RAM are volatile, meaning that they lose their

contents when the power is turned off.

DDRx

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DDRx SDRAM is a family of random access

memory that provides high bandwidth storage

of data for electronic devices.

There have been a number of DDR evolutions

starting with DDR then DDR2 and now DDR3.

Each new version is an improvement on its

forerunner with DDR3 being able to process

data at twice the rate of DDR2.

The physical layout for the DDR interface is

specified by the silicon vendors and published

in their layout guidelines and this has evolved

with each adaptation of the memory interface.

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VGA

Video Graphics Array, a graphics display

system for PCs developed by IBM.VGA has

become one of the de facto standards for PCs.

In text mode, VGA systems provide

a resolution of 720 by 400 pixels. In graphics

mode, the resolution is either 640 by 480 (with

16 colours) or 320 by 200 (with 256 colours).

The total palette of colours is 262,144.

Unlike earlier graphics standards for PCs -

- MDA, CGA, and EGA – VGA uses analog

signals rather than digital signals.

Consequently, a monitor designed for one of

the older standards will not be able to use VGA.

Since its introduction in 1987, several other

standards have been developed that offer

greater resolution and more colours, but VGA

remains the lowest common denominator.

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All PCs made today support VGA, and

possibly some other more advanced standard.

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ROM

Read – Only Memory is a computer memory

on which data has been pre-recorded. Once

data has been written onto a ROM chip, it

cannot be removed and can only be read.

Unlike main memory (RAM), ROM retains its

contents even when the computer is turned off.

ROM is referred to as being non-volatile,

whereas RAM is volatile.

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Most personal computers contain a small

amount of ROM that stores critical programs

such as the program that boots the computer. In

addition, ROMs are used highly in calculators

and peripheral devices such as laser printers,

whose fonts are often stored in ROMs.

PROM or Programmable Read - Only

Memory is another variation of ROM. PROMs

are manufactured as blank chips on which data

can be written with a special device called a

PROM programmer.

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HDD

A computer Hard Disk Drive is the mechanism

that controls the positioning, reading and

writing of the hard disk, which furnishes

data storage.

A hard disk drive / hard drive / hard disk are

not the same thing, but they are packaged as a

unit and either term can refer to the whole unit.

Hard disk drives can be found in desktop

computers, mobile devices, consumer

electronics and enterprise storage arrays in data

centers.

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Hard disk drive components

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Most basic hard drives consist of a number of

disk platters that are positioned around a

spindle inside a sealed chamber. The chamber

also includes read-and-write heads and motors.

The motor is used to spin the platters, which

hold the data, at up to 15,000 rotations per

minute. A higher rpm number results in faster

performance.

As the platters spin, a second motor controls the

position of the read-and-write heads that record

information to, and read information from,

tracks on each platter

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SSD

The main alternative to hard disk drives in PCs

and the enterprise are Solid - State Drives

(SSDs). Unlike hard disks, SSDs contain no

moving parts.

SSDs also have a lower latency than HDDs,

and are therefore often favoured to store critical

data that needs to be accessed quickly and for

applications with a high input demand.

They are more expensive than HDDs from a

price-per-gigabyte standpoint. Many enterprise

storage arrays ship with a mix of HDDs and

SSDs to reduce costs while providing better

performance.

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MULTITASKING

Multitasking, in an operating system. It allows

a user to perform more than one computer

task (such as the operation of an application

program) at a time.

The operating system is able to keep track of

where you are in these tasks and go from one to

the other without losing information.

Microsoft Windows 2000, IBM's OS/390, and

Linux are examples of operating systems that

can do multitasking.

As an example, when you open your

Web browser and then open Word at the same

time, you are causing the operating system to

do multitasking.

Being able to do multitasking doesn't mean that

an unlimited number of tasks can be juggled at

the same time. Each task consumes system

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storage and other resources. As more tasks are

started, the system may slow down or begin to

run out of shared storage.

Advantages of multitasking

Data can be copied and moved between

programs.

More productive, since dozens of

different program can be running at

once.

Programs that are updated can be seen

immediately. For example, if a new e-

mail is received you immediately

known.

Disadvantages of multitasking

Requires more system resources.

If on a laptop or portable device takes

more battery power.

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MULTIPROCESSING

Multiprocessing is the coordinated processing

of programs by more than one computer

processor.

Multiprocessing is a general term that can

mean the dynamic assignment of a program to

one of two or more computers working in

tandem or can involve multiple computers

working on the same program at the same time

(in parallel).

With the advent of parallel processing,

multiprocessing is divided into Symmetric

Multiprocessing (SMP) and Massively

Parallel Processing (MPP).

In symmetric (or "tightly coupled")

multiprocessing, the processors share memory

and the I/O bus or data path.

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A single copy of the operating system is in

charge of all the processors. SMP, also known

as a "shared everything" system, does not

usually exceed 16 processors.

In massively parallel (or "loosely coupled")

processing, up to 200 or more processors can

work on the same application.

Each processor has its own operating system

and memory, but an "interconnect"

arrangement of data paths allows messages to

be sent between processors.

Typically, the setup for MPP is more

complicated, requiring thought about how to

partition a common database among processors

and how to assign work among the processors.

An MPP system is also known as a "shared

nothing" system.

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MULTITHREADING

Multithreading is a type of execution model

that allows multiple threads to exist within the

context of a process such that they execute

independently but share their process

resources.

A thread maintains a list of information

relevant to its execution including;

The priority schedule,

Exception handlers,

A set of CPU registers,

Stack state in the address space of its

hosting process.

Threading can be useful in a single-processor

system by allowing the main execution thread

to be responsive to user input, while the

additional worker thread can execute long-

running tasks that do not need user intervention

in the background.

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Threading in a multiprocessor system results in

true concurrent execution of threads across

multiple processors and is therefore faster.

However, it requires more careful

programming to avoid non-intuitive behaviour

such as racing conditions, deadlocks, etc.

Operating systems use threading in two ways:

Pre-emptive multithreading –

The context switch is controlled by the

operating system. Context switching

might be performed at an inappropriate

time, hence, a high priority thread could

be indirectly pre-empted by a low

priority thread.

Cooperative multithreading –

The context switching is controlled by

the thread. This could lead to problems,

such as deadlocks, if a thread is blocked

waiting for a resource to become free.

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The 32- and 64-bit versions of Windows use

pre-emptive multithreading in which the

available processor time is shared such that all

the threads get an equal time slice and are

serviced in a queue-based mode.

During thread switching, the context of a pre-

empted thread is stored and reloaded in the next

thread in the queue. The time slice is so short

that the running threads seem to be executing

in parallel.

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CPU Core Structure

A processor core is a processing unit which

reads in instructions to perform specific

actions. Instructions are chained together so

that, when run in real time, they make up your

computer experience.

As the name suggests, single, dual, quad and

octa have 1, 2, 4, and 8 cores respectively.

Multi core processors are designed to perform

multi-tasking and parallel processing

simultaneously.

Single Core

A single core processor completes the entire

instruction cycle of all the instructions,

consisting of fetch, decode, execute, memory

access and write back within a single core.

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Dual-core

Dual-core refers to a processing unit that

includes two complete execution cores per

physical processor. It has combined two

processors and their caches and cache

controllers onto a single IC.

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Dual-core processors are well-suited for

multitasking environments because there are

two complete execution cores instead of one,

each with an independent interface to the front-

side bus.

Since each core has its own cache, the

operating system has sufficient resources to

handle most compute intensive tasks in

parallel. Hence the instructions can now be

executed by either of the cores, which is free to

handle them.

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Multi-core

Multi-core is similar to dual-core in that it is an

expansion to the dual-core technology which

allows for more than two separate processors.

This hold true for quad and octa core

processors.

From the point of view of multi-tasking, 1.2

GHz quad core is definitely better, even if the

clock speed is slightly less.

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Nanotechnology CPU Design

Nanotechnology in computers provides the

need for faster running computer processes at

cooler temperatures than traditional, transistor-

based computer components.

In traditional computing, transistors have used

silicon components as an affordable and easily

manufactured method to provide smaller and

faster computers and electronic gadgets, such

as netbooks, smartphones and personal

assistant devices. Such powerful gadgets at so

small a size produce too much heat, however,

reducing the effectiveness, performance and

longevity of the silicon components.

Nanotechnology in computing solves the heat

dilemma by providing improved processor

power at cooler temperatures and lighter

weights.

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Nanotechnology in computers makes use of

nanomaterials, tiny molecule-sized machines

that process information similarly to the

intricate and complex cells in a living

organism.

Similar to cells, nanomaterials exist on a

microscopic level, one nanometer measuring

one billionth of a meter, or 1/50,000 the

thickness of a human hair. Nanotechnology in

computing therefore operates on a minuscule

level.

Computer manufacturers create long,

microscopic strands of carbon atoms,

called carbon nanotubes, into tiny transistors

that provide twice the processing power of

silicon chips, while generating much less heat

and lighter components.

Nanotechnology applications offer more

efficient performance, which conserve power

and increase battery life for smaller, portable

electronic devices.

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Cache Memory

Cache memory is a small-sized type of volatile

computer memory that provides high-speed

data access to a processor and stores frequently

used computer programs, applications and

data.

A memory cache is a portion of memory made

of high-speed static RAM (SRAM). Memory

caching is effective because most programs

access the same data or instructions over and

over. By keeping as much of this information

as possible in SRAM, the computer avoids

accessing the slower DRAM.

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L1 and L2 Caches

Some memory caches are built into

the architecture of microprocessors. The Intel

80486 microprocessor contains an 8K memory

cache, and the Pentium has a 16K cache.

Such internal caches are often called Level 1

(L1) caches.

Most modern PCs also come with external

cache memory, called Level 2 (L2) caches.

These caches sit between the CPU and the

DRAM. Like L1 caches, L2 caches are

composed of SRAM but they are much larger.

Disk Caching

Disk caching works under the same principle as

memory caching. A disk cache uses

conventional main memory. The most recently

accessed data from the disk is stored in a

memory buffer.

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When a program needs to access data from the

disk, it first checks the disk cache to see if the

data is there. Disk caching can dramatically

improve the performance of applications,

because accessing a byte of data in RAM can

be thousands of times faster than accessing a

byte on a hard disk.

Smart Caching

When data is found in the cache, it is called

a cache hit, and the effectiveness of a cache is

judged by its hit rate.

Many cache systems use a technique known

as smart caching, in which the system can

recognize certain types of frequently used data.

The strategies for determining which

information should be kept in the cache

constitute some of the more interesting

problems in computer science.

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BIOS

The Basic Input/Output System is a ROM chip

located on all motherboards that allows you to

access and set up your computer system at the

most basic level. Examples of BIOS

manufactures are AMI, Phoenix etc.

The BIOS includes instructions on how to load

basic computer hardware and includes a test

referred to as a POST (Power On Self Test)

that helps verify the computer meets

requirements to boot up properly.

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If the computer does not pass the POST, you

will receive a combination of beeps indicating

what is malfunctioning within the computer.

The four main functions of a PC BIOS

POST

Test the computer hardware and make sure no

errors exist before loading the operating

system.

Bootstrap Loader

Locate a capable operating system, and the

BIOS will pass control to it.

BIOS drivers

Low level drivers that give the computer basic

operational control over your computer's

hardware.

BIOS or CMOS Setup

Configuration program that allows you to

configure hardware settings including system

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settings such as computer passwords, time, and

date.

BIOS is a program that is made accessible to

the microprocessor on an erasable

programmable read-only memory (EPROM)

chip.

When you turn on your computer, the

microprocessor passes control to the BIOS

program, which is always located at the same

place on EPROM.

When BIOS boots up your computer, it first

determines whether all of the attachments are

in place and operational and then it loads the

operating system into your computer's RAM

from your hard disk or diskette drive.

With BIOS, your operating system and its

applications are freed from having to

understand exact details about the attached

input/output devices. When device details

change, only the BIOS program needs to be

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changed. Sometimes this change can be made

during your system setup.

Although BIOS is theoretically always the

intermediary between the microprocessor and

I/O device control information and data flow,

in some cases, BIOS can arrange for data to

flow directly to memory from devices that

require faster data flow to be effective.

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Windows Registry

Windows Registry contains information,

settings, options, and other values for programs

and hardware installed on all versions of

Microsoft Windows operating systems.

For example, when a program is installed, a

new sub key containing settings like a

program's location, its version, and how to start

the program, are all added to the Windows

Registry.

When Windows was initially released, it relied

heavily on .ini files to store Windows and

Windows programs configurations and

settings. Although .ini files are still sometimes

used, most Windows programs rely on settings

made to the Windows Registry after being

installed.

To view and make changes to the Windows

Registry, the Windows Registry Editor may be

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used. In Windows 3.x, the Registry Editor was

known as the Registration Info Editor or

Registration Editor.

The Registry Editor allows you to view all keys

and values that are in the Registry as well as

change Windows, program, or driver values

you feel are necessary.

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Registry Root Keys (hive name)

When first opening the Windows Registry

Editor, it displays root keys that contain all

Registry values. The most common root keys

and the values:

HKEY_CLASSES_ROOT (HKCR)

Describes file type, file extension, and OLE

information.

HKEY_CURRENT_USER (HKCU)

Contains user who is currently logged into

Windows and their settings.

HKEY_LOCAL_MACHINE (HKLM)

Contains computer-specific information about

the hardware installed, software settings, and

other information. This information is used for

all users who log on to this computer and is one

of the more commonly accessed areas in the

Registry.

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HKEY_USERS (HKU)

Contains information about all the users who

log on to the computer, including both generic

and user-specific information.

HKEY_CURRENT_CONFIG

(HKCC)

The details about the current configuration of

hardware attached to the computer.

HKEY_DYN_DATA (HKDD)

Only used in Windows 95, 98, and NT this key

contained the dynamic status information and

Plug-and-Play information. This information

may change as devices are added to or removed

from the computer. The information for each

device includes the related hardware key and

the device's current status, including problems.

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Windows Registry values

Closed key

Like the folders seen in Windows Explorer

which contain the Registry sub keys.

Open key

When a key is opened the icon changes to an

expanded or open key and displays all its

contents and any additional sub keys.

String value

REG_SZ type. Allows for any string value to

be defined on a single line, such as a file path.

String array value

REG_MULTI_SZ type. Any multi-line

string value.

Expanded string value

REG_EXPAND_SZ type. Contains a string

with variables that need to be expanded. For

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example, c:\%windir%\example.exe could be

the same as C:\windows\example.exe.

Binary value

REG_BINARY type. Allows for attributes to

be defined in binary as either on or off (0 or

1).

DWORD value

REG_DWORD type. Similar to the binary

value, but capable of values being defined in

either 32-bit decimal or hex.

QWORD value

REG_QWORD type. Like the DWORD, but

stored as a 64-bit value.

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Protect Computer from Threat

Don’t be insecure.

The first step toward protecting your computer

is simply making sure it’s equipped with

antivirus software.

Keep current.

If you have antivirus software but don’t always

make sure it’s always updated, you may as well

just offer your computer’s sensitive data up to

hackers. With new strains of malware being

produced every day, security software must be

updated just as often to best protect your

computer.

Click with caution.

Never click on unknown email attachments,

shady ads or other suspicious links, and

keeping your web browser and its plugins

(like Adobe’s Flash) up to date.

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Bring backup.

If you’re not regularly backing up your

computer files, you risk losing them all in a

malware attack.

Surf with protection.

When you use a wireless connection, your data

is literally floating around in the air, and

anyone who knows how, can eavesdrop on

your computer. Free Wi-Fi is an unsafe public

network. The easiest way to protect yourself is

to connect only to secure networks: They

usually have a lock symbol next to them and

may mention “WPA” or “WEP encryption.

These networks garble up the data you’re

transmitting so it won’t make sense to anyone

trying to steal it.

Think complicated.

Some people use the same password for

everything; others make them too simple. Try

to get a mix of letters and non-consecutive

numbers for the best protection. And avoid

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having one universal log-in, so that if one

password gets hacked, you don’t risk

everything.

Install a firewall

A firewall enacts the role of a security guard.

There are of two types of firewalls: a software

firewall and hardware firewall. Each serves

similar, but different purposes. A firewall is the

first step to provide security to the computer. It

creates a barrier between the computer and any

unauthorized program trying to come in

through the Internet. If you are using a system

at home, turn on the firewall permanently. It

makes you aware if there are any unauthorized

efforts to use your system.

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Ergonomic rules

These are the rules designed to provide

optimum comfort and to avoid stress or injury.

Ergonomics related to computers seek to

alleviate stress conditions by focusing on a

number of different things, including:

Wrist support for the keyboard

Key board angle

Chair height and type

Back support

Lighting in the room

Placement of documents, phones, and

other frequently used items

Each of these things, and more, have a direct

effect on your comfort and the overall stress to

your eyes, joints, wrists, and other body parts

as you spend prolonged periods of time in front

of the computer.

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Computer ergonomics deals with the

placement and set up of desks, computers and

computer equipment, and lighting so that it

minimizes stresses and risks.

Computer Ergonomics - Working Positions

If you are working at a computer, the way you

sit and align your body will affect you. The

ideal situation and set up would include:

The top of the monitor should be

situated at or below eye level.

Head and neck are balanced and in line

with the torso, so you are sitting up

straight in your chair and not hunched

over the keyboard.

The elbows are supported and close to

the body, with the wrists and hands in

line with the forearms.

Lower back should be supported in an

ergonomic chair or with a pillow.

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Stools should be avoided when sitting

at a computer.

The feet should be flat on the floor.

Computer Ergonomics - Placement of

Components

Where the components of your desk and

computer are placed is also important to your

overall health.

Computer monitor. Ideally, your

monitor should be situated so you don’t

have to strain your neck and lean

forward to look at it. You don’t want to

have it too close or too far from you, as

this can result in blurred vision. In

addition, it should be placed in an area

where there is sufficient lighting and

reduced glare.

Key board: The placement and support

of the keyboard are also important, as

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continual typing puts you at increased

risk for carpal tunnel syndrome. Your

keyboard should be placed so that your

arms are parallel with the floor.

Computer mouse: The mouse should be

placed so that it allows for a straight,

neutral wrist position. You can use a

mouse pad with a special wrist support

so you can keep this neutral position.

Desk: Your desk should have sufficient

space for your computer, mouse, phone,

documents, and anything else so you

are not cramped or overcrowded. The

desk should also be made so a chair can

fit comfortably under it, and your knees

are not hitting drawers or supportive

structures for the desk.

Chair: Your chair should allow you to

be level with the computer screen while

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at the same time providing sufficient

support for your back.

Computer ergonomics allow you to work with

a computer more comfortably. The above rules

will help you to follow computer ergonomic

guidelines so you will have the least amount of

stress on your eyes and joints as possible.