Personal Computers and peripherals

Learn and buy computers and peripherals

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desktop computer

Introduction to the Computers

Computers are everywhere and it is affecting our daily lives in many ways. We are hearing about the newest way that computer is being used in our everyday life. No wonder we are in the era of Computer Revolution. Computers have now become an important part of our lives.

Till now, we have been using a typewriter for drafting commercial correspondence, a calculator for performing lengthy calculations and files for maintaining records. Now, we can do all our correspondence, calculations and record maintenance on a computer at a much faster speed and less effort. Personal computers are now having far better facilities than that of a typewriter or a calculator or a file recorder. It has huge applications in multimedia and entertainment.

Computer as we defined are huge computing device with high speed and reliability. All the instructions given to the computer are done correctly and with a speed that sometimes wonders us. Till 20 years ago computers are used only in scientific works or in big organizations. Now Personal computers are every where. Every one is getting benefited from it. It is a video game for young people, calculator for a scientist, file manager for office clerk, music system for listeners, TV/Video Theater for viewers or an encyclopedia for a student. Surely Personal Computer has a role in every body’s life.

Again the ability to connect one computer to another one at the remote end, makes it valuable for Telecommunication, Banks, Travel Companies and other communication industries. Even common people are getting benefited from the computer network. Internet is one of the major sources of information and entertainment.

This tutorial is made with a thought that it will help those people who purchase a new computer or is planning to do so but have no primary knowledge about it. In this tutorial you can gather enough knowledge on Personal Computer and It’s Peripherals to get rid of your fear for it. Again you can use it as a text-book to start your journey towards computer’s world. Even people from technical background can get extra information from it.

If you are going to buy a new PC and going to be connected to the internet or already done so take a look in our tutorials. It will help you to understand the world of computer and Internet in a better way.


Popular Brands

There are popular brands of personal computers. A branded computers comes as an assembled box. Brand decides the motherboard, CPU, memory, graphics cards etc. We will not have enough flexibility to alter the components during purchase. Some brands gives the flexibility to choose items based on the customer's need.

desktop computer brands

These are the poplar brands available.

  • HP- HP is the oldest brand in personal computers. They acquire Compaq and their products are known for good brand values and trust.
  • DELL - Dell is known for their desktop computers. Dell makes all types of personal computers and lifestyle products. They offer trustable products with great warranty coverages.
  • Lenovo - Lenovo was formerly known as IBM computers. Lenovo PC makes from China took over this brand. Lenovo computers are known for build qualities and brand values.
  • Asus - Asus makes good branded personal computers. They also make motherboards in various categories. They have product ranges for all types of consumers.
  • Aser - Aser is known for a wide range of products with good value for money.
  • Microsoft - Microsoft is known for operating system and office softwares. They also make branded personal computers and gaming units. Microsoft surface desktops are popular among highen customers. Microsoft is also most popular in gaming console market and Xbox is a brand for high end gamers.
  • Apple - Apple is known for their Macintosh personal computers. They also make their own operating systems OS X for their own computers. Apple products are costlier in terms of price ranges but the best in quality, design, style etc.

Now there is a choice to select a custom made personal computer. Here we have to purchase each component by ourselves and then we have to fit on our own. Here one of the risk factors is incompatibility. So we have to consult an expert prior to finalizing the components. Branded PC vendors often include an OEM version of a licensed operating system like Windows 10. Here we have to purchase the same or we have to choose a free distribution of Linux.


Desktop types

Desktop personal computers come in many varieties of form factors and sizes. These are some popular ones : Standard Tower-type, Standard Desktop type, All in one AIO, Mini Tower, Mini PC, Stick PC, Diskless thin client, Single-board computers.A standard tower type PC is a very generic computer type that includes all the generic features. We are primarily discussing this type of personal computer and its peripherals.

all-in-one
All-in-One
desktop-unit
Desktop computer
tower-desktop
Desktop tower
micro-tower
Micro Tower
thin-client
Thin Client
mini-pc
Mini PC
stick-pc
Stick PC


Parts of a Computer

desktop computerA personal computer is a collection of separate items working together as a team. A laptop and tablet are miniature piece of computers. They often include some of the parts inside itself as an integrated device. A desktop personal computer gives a good understanding on how each of its separate components are connected and makes a whole working system. Some of these components are basic fundamental units and essential for its operation. Others are simply make working more pleasant and efficient. Adding extra items extends the variety of tasks you can accomplish with your machine. The essential and some optional components are listed below:

Basic ComponentsOptional Components
System UnitFloppy disk Drive
MonitorCD-ROM/DVD Drive
KeyboardPrinter
MouseScanner
Hard Disk DriveScanner
Modem
Network Interface Card
Sound Card
UPS/CVT

The System Unit

System unit The system unit is essentially a box that holds all the system components in it. It is sometimes called a computer cabinet. The most common components inside are Motherboard, processor, memory unit, SMPS, and the ports to interface the computer’s peripherals. The system unit comes in two different shapes the desktop and the tower type. Nowadays tower type system units are very common.

Front of System unit

Power On/Off: Generally all PCs have the main power button on the front side of the system unit. This switch is used to bring the system in powered on condition as well as this is used to shut it off. This is often a toggle. Most of the newer system units have a soft press button. Newer ATX cabinet power is automatically cut-off after we pack up the pc from windows.

Reset Button: This button is often used to restart the computer without disconnecting the Power. If the system goes to a hung state i.e. if it doesn't answer any commands, this push button is employed to bring the pc again into working condition. Pressing this push-button will cause a restart thus all the work that hasn’t been saved within the session will be lost. So it is advised to use the keyboard Alt+Ctrl+Del buttons altogether to pack up the appliance which isn't responding in windows then save your work and reboot the PC.

Lights: There are two or three LED (Light Emitting Diodes) indicators within the front panel indicating power, hard disc read/write activities. Diskette and CD/DVD Drives even have indicating LEDs. They automatically glow when data is being read from or written thereto drive. In some old PCs have a display unit where the speed of CPU is displayed in 7 Segment LEDs.

Floppy Disk Drive: PC can have either 5.25 " or 3.5 "" floppy drive or both. it's used for storing or retrieving data on to floppy. Each drive features a slot at the front of the system unit, where the floppy has got to be inserted for reading or writing purposes.

CD/DVD Drives: These drives are inserted within the bigger drive cases above the three ½ “ floppy drive. Both CD and DVD drives feature a tray where CDs are inserted and this tray is automatically closed or opened with a play push on the drive, a bit like a drawer.

Back of the System Unit

The back of the System unit contains all the interfacing ports to plug external devices to it.

Power IN and OUT Sockets: Cables plugged into these sockets carry AC power from the wall socket to the SMPS (Switched Mode Power Supply) unit of the cabinet and from the SMPS unit to PC’s monitor.

SMPS Fan Housing: Besides the facility of In and OUT AC socket there is a cooling fan for the SMPS unit. It helps in removing hot air from the SMPS and system unit and keeps the inner environment cool.

PS/2 port: Keyboard cable is plugged to the system unit by a PS/2 port. This port is round in shape and all the pins are arranged in circular order. The mouse connecting port is also a PS/2 port. Modern

Serial Ports: Serial ports are sometimes called communication port or COM port. There are two COM port COM1 and COM2. The size of COM1 is larger than that of COM2. COM1 has 25 pins and is used for connecting Modems. COM2 is 9 pin port used for interfacing serial mouse. D-type connectors are to interface those ports.

Parallel interface: Parallel port is like COM1 port with 25 pins. it's called LPT1. One PC may contain quite one LPT port. Printers are typically plugged into those ports.

Joy Stick Port: it's sort of a parallel interface. it's wont to connect Joysticks for enjoying interactive games.

Video/Monitor port: Video / Monitor port is extremely almost like COM2 port except it's quite 9 pins. This port is named AGP (Accelerated Graphics Port).

Audio jacks: There are three audio jacks from the sound card. One is Audio Out, one Audio In and One for MIC.

USB Ports: The ports are very small in size. USB (Universal Serial Bus) is additionally an interface but rate is a large amount quite the interface. Mouse and modems are usually connected to those ports.

Compartments for Expansion Cards: PCs are easily expandable- to supply a modem, sound or faster graphics. within the empty PCI slots internal modems, network interface card or faster graphics card are often plugged.

Inside the System Unit

All the precious components of PC is in side the system unit. Inside the unit all the components work together to offer you the service that you simply need. Computer takes the input form the data input device like keyboard process the info in CPU holds the info in memory and provides out put within the output device like monitor.

  • Motherboard: All the electronic components within the system unit is mounted and connected together by the motherboard. they're also called main board. CPU board may be a piece of fibre glass and interconnection is formed via metal lines usually fabricated by cupper. this is often also called a computer circuit Board (PCB). Mother board holds all the connecting ports, interfacing slots and essential chip like main processor, PCH etc. Motherboard or sometimes called main board may be a multilayered computer circuit board. The system bus lines are routed within the inner layer and within the upper layers there are some IC sockets to attach the IC/ Chips. Intel chipsets available in market for all available CPU types and generations.
  • Central Processing Unit (CPU): The microprocessor, or central processing unit (CPU), is that the computer’s most vital component. It does all the arithmetic and logical operations.
  • Math Co-processor Slot: A math co-processor, present in some PCs, assists the CPU in performing its mathematical operations (if program are designed to use it).
  • RAM Chips: When a computer is switched on and is running a program, RAM (Random Access Memory) is employed for purposes like holding the program and its data. But when the PC is transitioned , anything held in it's lost.
  • Empty RAM Chip Slots: These slots are kept for adding extra RAM chips or modules to computer’s memory. Usually there are three slots for RAM module, one is occupied and other two are kept for future upgrade.
  • Floppy Disk Drives: there's two diskette drive drawer accept a diskette . there's a SCSI connector to attach SCSI drives to the Motherboard.
  • hard disc Drive: there's two or three drive drawer for Hard Disk and CD/DVD Drive. There are two IDE connector, Primary and Secondary to attach four IDE devices to the CPU board .
  • SMPS Box: SMPS is Switched Mode Power Supply within the system box. it's a separate unit within the system unit. It converts 230V AC power supply to five and 12 V DC and provides the availability to all or any components of the CPU board .
  • Display Adapter Card: Every computer must have a display adaptor card in it. Often the cardboard is made within the motherboard. If we would like to feature or motherboard has no inbuilt display then one AGP port is there to plug the Display card. The slot is extremely almost like PCI slot.
  • Expansion Slots: There are ISA, PCI, PCIe, AGP slots given in motherboards. Graphics card, internal modem, sound card or network interface cards are often interfaced within the slot.
  • ROM Chips: Read only memory (ROM) chips have data written on them, during manufacturing that tells the CPU what to try to to once you turn on your PC. the info always there, even once you switch the PC off.
  • CPU Support Chips: These chips help the CPU to manage all the parts of the pc .
  • Speaker: The speaker emits the computer’s sound output within the sort of beeps.

Central Processing Unit (CPU)

CPU Intel vs AMD Central Processing UnitAs the name denotes, all the processing takes place inside this unit. CPU is the brain behind all the operations. CPU performs two types of operations arithmetic and as logical operations. CPU contains a collection of registers to hold the operands and results . Arithmetic and Local unit or ALU is a part of which performs these operations. Control unit or CU and bus system unit interacts with control, address and data bus units. CPU has a coupleIt is also referred as processor or microprocessor. The instructions written with a sort of computer programs are compiled to assembly codes which are administered by the CPU in sequence. Thus a program instruction can control can control the whole working of the PC as CPU interacts with every a part of the pc.

The power of CPU lies in its ability to hold out these actions rapidly and flawlessly. The processing capability of a PC is measured in terms of amount of knowledge processed by the CPU in one operation and therefore the time taken for this operation.

Buying CPUs (factors and brands)

Speed of CPU

The speed of a CPU is measured in megahertz (MHz) and gigahertz (GHz). A computer features a central clock that keeps all the components in time with one another . One hertz is that the same time as that of a clock tick and one megahertz is adequate to a million ticks per second. CPUs like 80486 Pentium etc had a speen around 100Mhz. Now a days this speed reaches around 1.2 Ghz to 3.8Ghz. Overclocking, turbo boost are two additonal features of CPUs used for gaming and performance fields.

CPU Cores

There is a limit of transistor and solid state electronics. CPU speed cannot be increased to infinity. Now to overcome this processor manufacturer came with an idea of multicore and multi processor CPU. These type of CPUs are a collection of smaller CPUs inside one chip. So there are multiple execution context depending on the number of cores present in the CPU socket. The

CPU thread

CPU thread design comes from the hyperthreading technology. A thread is a small execution unit of the core which can work parallely with other threads. A CPU core often includes two threads. The main instruction queue of one core divides between these two threads. These two threads executes the instruction in parallel to boost the overall performance of the the core.

CPU cache memory

CPU has a small amount of memory known as cache. CPU fetches instructions and data from main memory and they are used for frequent access. The amount of cache makes the . However cache memory are very expensive and they increase the cost of the CPU.

CPU temperature

CPU does the main processing and it generates lots of heat during runtime. CPU often includes a head sink and a fan. CPU chip is placed on the CPU socket. CPU’s upper front side is made with a metal packs. This headsink is mounted on top of metal top. A heat sink paste is applied when fixing this unit. A fan

CPU IO interface

CPU interface to memory and input output devices via bridges. Earlier motherboard used to hold two IO bridges named as north bridge and south bridge. North bridge interfaces with main memory and very high speed devices. South bridge is for interfacing low speed devices. Newer CPUs and chipsets has eliminated the need of north bridge chip. CPU itself contains a north bridge as the integrated memory controller and PCI root port.

CPU power

CPU consumes majority of the power of the entire computing unit. CPU may not be executing all the times and they will be in sleep or paused state. To deal with these situations CPU comes with various power states. Multicore CPU environment we call the main CPU (first core) as base CPU or BSP used primarily for system and OS usage. Other CPUs are for application processing called as APs. Depending on the load and tasks some of the APs might be in sleep state. When any core or CPU becomes idle they goes to power saving state and jumps to a lower base frequency. This feature is known as speed step. CPU saves lots of power using this technology.

CPU brands

Intel and AMD are two market giants for the CPUs used in desktop market. There are ARM based SBCs available but they are used mainly for educational purposes. Intel generally release CPUs of 3-4 types. Core i3 family is for basic and entry-level users. Core i5 is for professional users. Core i7 and i9 are for high-end users who deals with games, video/audio/image editing etc. AMD has some similar CPU falilies. AMD Athlon, FX, Ryzen CPUs are some generations. Latest is Ryzen series and they are Ryzen 3, 5, 7 and they are equivalent to Intel's i3, i5, i7 usage. Ryzen CPUs however have better CPU cores and thread counts than Intel. When purchasing CPUs we beed to consider the price, base frequency, cache size, performance, core count, brand and lots of factors.


Motherboard

ATX Motherboard
atx-motherboard
Micro Motherboard
micro-atx-motherboard
Mini ITX Motherboard
mini-itx-motherboard

Mother board holds all the component parts, ports, interface cards, memory, essential chip like main processor. Motherboard or sometimes called main board may be a multilayered computer circuit board. The system bus lines are situated within the inner layer and within the upper layers there are some IC sockets to attach the IC/ Chips. Intel chipset available in market.

A motherboard is made on the base a CPU category. It will have a CPU socket and DIMM slots. CPUs and DIMMs with same PIN compatibility can be attached. A motherboard can support few CPUs in the same category and memory slots of the respective generation. Example a motherboard with Intel® Core™ i5-8400 Processor support can support only DDR4 memory slots and Core i5 pin compatible family processors. Other CPUs and memory modules from DDR3 or below will be pin compatible. Motherboard has a CPU socket and DIMM slots. There will be min 2 DIMM slots or more. Motherboard should include an AGP port or PCIe for graphics cards. There will be few slots PCIe slots for add-on cards. There can be slots for ISA and legacy PCI cards.

Motherboard can have different form factors depending on the design. Atx, EATX, Micro ATX, Mini ITX Motherboard are the common form factors. Motherboard for single board computers, all in one PC and miniature PC comes with a custom form factor made exclusively made by the vendor. Motherboard decides which cabinet box should be used.

Buying Motherboard (factors and brands)

  • Motherboard Size - Motherboard depends on which formfactor has been chosen.
  • Memory slots - There should be at least two memory slots available on motherboard. A high end motherboard inclues 4-8 DIMM slots.
  • Ports Slots - A motherboard should include all communication ports, and slots for add-on cards
  • Onboard devices - A motherboard often includes a GPU, sound card, LAN/ethernet controller and USB controllers.
  • Motherboard price - Motherboard price often depends on the brand.
  • Usage/Profile - Basic/Normal: Min 2 DIMM slots, CPU i3, i5, i7. Onboard graphics, Advanced: Add on GPU, 4-8 DIMM slots
  • Motherboard brands - ASRock, Asus, Biostar, EVGA Corporation, Gigabyte Technology, MSI (Micro-Star International), Intel.


Computer's Memory

DIMM memory CPU is the brain behind all the operations however CPU needs memory for getting next instructions and also processing the data. CPU fetches the instruction queue from the code section of the program. This is located in primary memory. Once the CPU has carried out each instruction, it fetches data operands from main memory. Data, heap, and stack sections are used. Data operands are processed in ALU and stored again stored in primary memory. Primary memory is divided into two memory modules ROM and RAM.

ROM is Read-only-memory and this is used to store boot firmware or BIOS. When we power on the computer, CPU executes the code located from ROM chip.

Another important primary memory is RAM or Random-access-memory. As the name suggests, it is accessed randomly in point of time in any location and it is used for reading and writing. RAM memory modes comes as DDR modules with a specific capacity of memory. Memory is defined as bits. One bit is a single binary digit of information. The minimum amount a CPU can access in one shot is one byte of memory. One byte is composed of 8 bits. 1024 bytes is called kilobytes(KB) and 1024 kilobytes is one megabytes(MB). Again 1024 megabytes is one gigabyte (GB). A 32bit CPU access memory in 32 bit word length at any time. Each processor has a fixed address lines. 32 bit processor can access 2^32 -1 i.e. 4GB of memory. 32 bit CPU can access up to 64GB of memory using physical address extension (PAE). 64 bit CPU often has 42-48bit of the address line. It can access up to 2^48 -1 bytes depending on CPU SKU.

CPU does not access main memory all the time it needs. It has a high speed memory called cache memory. CPU fetches memory to data cache with a length of the size of cache line. After that CPU performs temporary operations in cache memory. Cache memory is way faster than RAM and thus this boosts the performance. CPU even fetches instructions from main memory to the instruction cache memory.

x86 processor defines a memory map which tells the region of the address space mapped to memory or MMIO space. Computer after power on boots up to legacy processor mode of x86 where only lower 20bit of the address lines are mapped. This is called real mode of execution. Lower 20bits or 1MB lower RAM is called base memory. Lower 640kb is used as RAM. Address between A0000-BFFFF is used for VGA frame buffer MMIO. C0000-DFFFF are used for mapping PCI adapter ROMs and E0000-FFFFF region is used as BIOS ROM area. BIOS ROM is stored on a flash chip located in the motherboard.

Processor switches to a protected mode of operation during boot loader execution. This gives CPU to address higher memory region above 1MB. Protected mode deals with a granule of memory called “Page Memory”. The typical size of a page is 4KB. Processor sees the entime memoy as a collection of pages. Modern processor has memory managemnt unit called MMU. Operating system programs page table and page directory to map the entire region of physical memory. Now MMU can work on a uniform memory region of 4GB for each process and this mechanism is called “Virtual Memory”. Operating system creates different physical pages for each process but the virtual layout of each process looks same. Virtual memory gives the facility of shared memory pages and protection for private memory pages. Virtual memory also deals with the condition where physical memory is limited and swapping is used to swap pages to secondary memory. “Secondary Memory” is mainly a part of permanent storage devices like Hard-Disk, floppy drives etc.

Buying DIMM memory (factors and brands)

  • Memory form factor - Memory comes in the form of DDR modules. There are primarily two basic form factors. Desktop and laptop. Smaller for factor modules are used primarily in laptops and they can be used in all in ones, mini personal computers.
  • Memory generations - Memory design comes with DDR generations. GEN3 and GEN4 are common now a days.
  • Memory Speed - Memory generation decides the range of speed it can operate. Speed of the memory is measured in clock speeds. The higher the frequency the better the performace.
  • Memory capacity - DDR modules comes with a size and
  • Memory channel -
  • Brands - Corsair, Micron, G.Skill, Kingston, HyperX, Hynix, Adata, Crucial.
  • Usage - Basic: 2GB, Normal: 4-8GB, Advanced: > 8GB.


Graphics processing unit

Computer GPU card Graphics processing unit or GPUs are the most important part of a computer as this is the primary output device. Any multimedia PC is not complete without a graphics card. Servers and headless computing units may not have GPUs since they are remotely accessed via serial port or remote telnet terminals. Programs running in the CPU produce outputs and these are presented in display devices.

GPU can operate on text mode or graphic mode. Text mode converts the ASCII characters to character fonts and display the font bitmaps. Graphic mode delas with individual pixels. A GUI based operating system creates it's actually process the alphanumeric display information and convert it to RGB signals send it to the monitor.

GPU has a dedicated or shared memory. This memory is often known as framebuffer or video RAM(vRAM). CPU processes the data to this framebuffer and GPU is responsiblde for giving video output signals. The video output signals are given to different ports like VGA, S-Video, DVI or HDMI port. A monitor is attached to this port.

There are several configuration of video card like CGA (color Graphics Adapter), EGA (Enhanced Graphics Adapter), MCGA (Multicolor Graphics Adapter), VGA (Video Graphics Array, SVGA (Super Video Graphics Array), XGA (Extended Graphics Array) etc.

SVGA is now extensively used. SVGA supports 640x480, 800x600, 1024x768 resolution and 16, 256, 16Bit, 24Bit True color display. Video Cards are some times internally integrate the CPU board or are often externally plugged in an AGP (Accelerated Graphics Port) slot or PCI express port of motherboard.

New motherboards include an onboard GPU chip. These GPU is for primary display of the desktop screen. A regular work like , watching videos etc can be done. An external graphics card are often required for some special purposes. A drapcichs designer, Video editor, engineering software, multiple display system, video game developer or video gave player ofne add an external graphics card. Graphics cards often offloads video and graphics workload from main CPU and system runs much faster.

Buying GPU/Graphics card (factors and brands)

  • Graphics memory(vRAM) - THis is the size of GPU ram on the card. A basic card contains 4MB to 64MB of graphics memory. A high end Game and video processing GPU contains GBs of vRAM.
  • Processing unit - GPU vendors put more powerfull GPU processor for more powerful cards. These CPUs often includes multicores. They often require additional fans and cooling when performing at the peak level.
  • Video and rendering engine - GPU cards give rendering offloading from main CPU. They follows OpenGL and DirectX standards for softwares.
  • Cost - As we go to the highend spec of GPU and vRAM we see the increate in price.
  • Usage - Basic: Onboard, Normal: 1-4GB, Advanced: > 4GB.
  • Brands - Nvidia, MSI, ATI, AMD, Asus, Intel, EVGA, Gigabyte, Sapphire, Zotac.


Computer's Monitor

Computer monitor A PC’s monitor works sort of a television screen. It displays text characters and graphics in colours or in grey scale format. The image we see on the screen, is formed from tiny dots called pixels. A monitor is additionally called a screen, display or a CRT (Cathode Ray Tube) or LCD TFT. Whatever is typed on the keyboard gets displayed on the monitor screen. Also whatever a program is executed, the image is displayed on the monitor. On the screen, the results are shown only temporarily. A cursor may be a small double line that blinks rapidly indicating current position on the screen. Now, if you strike a letter key, then that alphabet are going to be shown at the present cursor position and therefore the position of the cursor is shifted one position to the proper . The cursor, therefore, marks the purpose where subsequent character are going to be displayed on the screen, once we press it on the keyboard. There are differing types of monochrome (BW) also as color monitors available within the market. the main difference is their resolution (i.e. the sharpness of the image on the screen.) Monitors having a better resolution are costlier and that they are used for specified jobs like creating graphics and multimedia.

Buying PC Monitor (factors and brands)

  • Display technology - CRT, LCD, TFT
  • Display resolution - HD 1080p, HD ready 720p
  • Aspect ratio - 4:3 and 16:9
  • Screen Size - 15", 20", 22", 27" etc
  • Rotation and alignment - 360 degree, align in vertical
  • Multimedia speakers built-in
  • TV tuning
  • Smart TV & aaps
  • Connector - VGA, DVI, HDMI, wifi
  • Usage/Profile - Basic/Normal: 15-20", Advanced: 22-32"
  • Monitor brands - Acer, Alienware, Dell, AOC, Apple, Asus, BenQ, HP.


Computer's Keyboard

Keyboard A Keyboard looks like a type-writer in front of the PC. Keyboard is a primary Input device. All the text inputs, special key inputs and commands are given through a keyboard. Keyboard acts as the primary input device. Many BIOS vendors halt the system during power on in case of an absence of a keyboard. When we press any key, the corresponding character is displayed in the screen. Every time we give a command or input, we have to complete the operation by pressing “ENTER” or “RETURN” key.

Buying PC Keyboard (factors and brands)

  • Types: Wired and Wireless
  • Keys, Numpad, function keys, multimedia controls
  • Wireless range, battery life
  • Brands - Zebronics. Dell. Logitech. Redgear. Quantum. Amkette.
  • Usage - Basic/Normal: Wired basic keys, Anvanced: Gaming and multimedia keys


Computer's Mouse

Mouse A mouse is a hand-held pointing device that allows the user to control the PC without having to type in instructions at the keyboard. Mouse is a secondary input device. Graphical operating system requires a mouse to operate properly. Modern Applications provide menu driven options for various commands like file open, save or printing. They are easily operated with the help of a mouse.

Buying PC Mouse (factors and brands)

  • Types: Wired and Wireless
  • Optical sensor
  • Scroll button, Gaming buttons.
  • Wireless range, battery life
  • Brands - Logitech, Microsoft, Apple, Dell, HP
  • Usage - Basic/Normal: basic buttons, Anvanced: Gaming and multimedia buttons


Floppy Disk and Drive

Floppy Floppy disks were of course the most useful and economic storage device ever made. Floppy disks were widely used for exchanging small text and document and multimedia files. Earlier days people used to keep very important information like personal documents, project reports, research papers etc. on hard disk. Those days hard drives were not much reliable and used to fail. To prevent data loss people used to copy onto floppy disks for backup.. The advent of USB pen drives and the removal hard drives have replaced the need for Floppy disk drives. So floppy drives have been discontinued in modern personal computers.

Why Floppy Disks and drives are obsolete?

  • Capacity - Only 1.44mb or 2.8Mb possible
  • Speed drive speeds are very slow
  • Size and form factor - Bulky relative to USB pendrive or SD cards
  • Easily gets bad sectors. Short life and not reliable.
  • Brands - Sony
  • Alternatives - USB pendive, micro SD, SD cards, removable harddrives.


Hard Disk Drive

HDDs For storing personal information of large size permanently or setup an operating system and application software needs a permanent storage device. Hard-Disk is the one of the most preferable choice as permanent storage. They are attached to the drive case permanently and connected to the mother board by IDE, SATA, SAS cable. Typical hard disk capacity is from 20GB to 2TB available in the market. Thus information storage capacity is at least 1000 times the old days floppy disks. Again they are lots faster running in 7200 r.p.m. Solid state drives are a new addition in the hard drive technology and as the price are reducing they are gradually replacing HDDs in modern computers.

Buying Hard Disk Drive (factors and brands)

  • Speed of disk - 7200 rmp
  • Data read and write speed
  • Capacity
  • Form factor
  • Connection type IDE/ATA, SATA, SAS
  • Brands - Western Digital Seagate Technology Hitachi Toshiba HGST
  • Usage - Basic: 40GB, Normal: 80GB- 1TB, Advanced: Multiple drives

Solid State Drives

SSD HDDs Solid State Drives are the variations of harddisk drives which stores the data in solid state electronics instead of magnetic rotating disks. These drives do not have any rotating parts. So it is most efficient in power. There is no noice or vibration with the drive. They are very slick in size and formfactor. Solid state drive were expensive initially. Now a days price is dropping and people are replacing older HDDs with these newer SSDs. SSD drives can be connected via SATA port with the motherboard. Some new motherboards are including M.2 slots where SSDs can be attached via SATA or NVMe/PCIe.

Buying Solid State Drives (factors and brands)

  • Capacity
  • Form factor
  • Cost
  • Connection type SATA, SAS, PCIe NVMe, eMMC
  • Brands - Intel SSD/Optane, Samsung, Toshiba, Adata, HP
  • Usage - Basic: 32-64GB, Normal: 128GB- 512TB, Advanced: 1TB


Removable drives

Removable HDDs Removable drives are new addition in market. They are basically flash based solid state devices. Usually we connect through USB 3.1 or 2.0 connector or through SD card interface.

  • SD card - SD card and micro SD cards are small and easy to carry.
  • USB pendrives - They are a size of a thumbs.
  • Removable Hard drives- They are new addition in market. Useful for backup of video and audio files.

Buying Removable drives (factors and brands)

  • Capacity
  • Form factor
  • Cost
  • Connection type USB, SD card slot, MMC
  • Brands - Samsung, Sandisk, Transcend, Kingston, Lexar, Micron, Intel SSD/Optane, Samsung, Toshiba, Adata, HP
  • Usage - Basic: 32-64GB, Normal: 128GB- 512TB, Advanced: 1TB


CD-ROM Disc and Drive

CD ROM drive CDROM means Compact Disc Read Only Memory. CDROM drive is one of the useful removable drives on the computer. CD-ROMs are widely used for exchanging software and backup of personal information. The disadvantage of this drive is once the information is written on the disk can not be altered again until it is a rewritable disc. CD-ROMs are becoming popular because of its low price and high storage capacity. Typical CD ROM disk can store information capacity upto 500-750MB. They are normally used for setup disks and Backup of personal documents. It is becoming more popular because it can store 90 minutes of PCM sound tracks or hundreds of MP3s or even one hour of full-screen MPEG video.

Buying CD ROM drive (factors and brands)

  • CD ROM read speed
  • Write speeds 1x, 2x, 4x, 8x etc
  • Wifi distance range
  • Brands - Sony, Dell, HP, Asus
  • Usage - must need


DVD (Digital versatile Disk)

DVD drive DVD or Digital Versatile Disc or Digital Video Disk is an extension of CD-ROMs. They are very similar to the CD-ROMs in terms of storage and technologies used in these drives. Both are based on optical principle of storage. The main difference between the CD and DVD are the storage capacity and density. One single DVD can store from 4.3 GB to 17 GB of data information. Thus one high resolution MPEG2 encoded full-screen motion picture can be fitted in one disc which used to come in a set of 3-4 CD ROMs. Again the sound quality would be more accurate as theater like Dolby Digital Surround Sound and be decoded in different regional languages.

Buying DVD drive (factors and brands)

  • DVD ROM read speed
  • Write speeds 1x, 2x, 4x, 8x etc
  • Wifi distance range
  • Brands - Pioneer, LG, Sony, Dell, HP, Asus
  • Usage - must need


Computer's Printer

Printer Printer is a device that produces ink based outputs of numbers, alphabets, graphs, images, etc on actual paper. After a digital document been created on a computer using a word processor, you can send it to a printer for a 'hard copy', generally known as a print out. The speed of the printer is rated either by 'pages per minute' (ppm) or by 'character per second' (cps). The more the dots per inch, the more detailed is the output. Printers come with different shapes and different printing technologies are behind. There are three types of printing technologies used in printers. Based of the technologies they are named as- Dot Matrix printer, Inkjet Printer, Laser Printer.

Buying Printer (factors and brands)

  • Printing resolution
  • Speed of printing one page/pages per minute (ppm)
  • Wifi, USB, Ethernet, connectivity
  • Driver support and additional softwares
  • Brands - Epson. HP. Konica Minolta. Ricoh. Toshiba.
  • Usage -Advanced: Only for DTP/office/document work.


Computer's Scanner

Scanner A scanner is a device that can digitize and transfer an photograph or hand written notes or pages of book to the computer. It acts like a photocopy xerox machine. Just instead of making another copy of it on to the paper, it stores it in the computer. Scanners can scan typed or handwritten text, graphs, diagrams and photographs.

Buying Scanner (factors and brands)

  • Scanning resolution
  • Speed of scanning one page
  • Wifi, USB, Ethernet, connectivity
  • Driver support and additional softwares
  • Brands - Panasonic. Image Access. ibml. Contex. Epson. Canon. Fujitsu. Kodak
  • Usage - Advanced: Only for DTP/office/document work.


SMPS

SMPS Inside a system unit, there is a power converter that converts the AC main 230V supply to various levels of DC voltages like 1.1. 1.2, 1.3, 1.5, 2.5, 3.3, 5, and 12V DC. There DC power lines are feed to the various parts of the computers. SMPS is the abbreviated term of Switched Mode Power Supply. It is composed of a step-down transformer and diode rectification circuits. After that switching transistors are used. This unit produces heat and fans are attached for cooling. This is located at the backside where we plug the AC power cable.

Buying SMPS (factors and brands)

  • Brands - Antec, Corsair, Enermax, FSP, OCZ, PC Power and Cooling, Seasonic, Silverstone and XFX
  • Usage - Must need


CVT

CVT Constant Voltage Transformer or CVT gives a constant AC voltage level even if supply voltage is varying. Domestic power supply is not good for a delicate computer. The voltage level is not stable and often fluctuates. This fluctuation of voltage may cause damage to the SMPS unit and other valuable units of the system. So computer should be connected to a stabilized power supply for reliability and security. CVT is a voltage stabilizer for computer systems.

Buying CVT (factors and brands)

  • Service and maintenance
  • Brands - APC, Microtek, Zebronics, any Local
  • Usage - Needed for all users


UPS

UPS UPS or Uninterrupted Power Supply, as the name suggests is a power supply that keeps the PC’s power supply voltage uninterrupted during the power cuts. UPS contains a DC battery and can act as an inverter when there is no power. UPS automatically switches to a backup power source during the power cuts. There is a fast switching circuit which turns on the inverter mode and there is no interruption in the supply voltage to the PC. It prevents the computer from sudden power loss and the user can save all the pending work. Computer's hard disk is the most common device which is going to be affected due to sudden power loss. Hard disks may get damaged or some portion of stored data may be lost. Computers are safe when UPS is used. No more loss or damage of data or device in the system. UPS also acts as a CVT.

Buying UPS (factors and brands)

  • Backup time period
  • Battery life
  • Service and maintenance
  • Brands - APC, Microtek, Zebronics, any Local
  • Usage - Needed for all users


Network Interface Card

NIC Network interface card or NIC is used to connect two or more computers together. It can be used for local area network connection using RJ45 conttectors and cables. It is one type of modem however it can not be interfaced with a telephone line. The normal data rate for NIC are much higher than data rates of telephone lines and they are 1Mbps, 10Mbps and 100Mbps. 10Mbps NIC are called Ethernet. These are based on CSMA/CD (Carrier Sense Multiple Access with Collision Detection) network topology. 100Mbps NICs are called Fast Ethernet. Gigabit ethernet card can support upto 1GBits per second. Earlier computer chipsets do not used to have a network card on the motherboard. Now a days they come as a part of motherboard and they are known as LAN on motherboard or LOM.

Buying NIC/Ethernet card (factors and brands)

  • Ethernet speed 10Mbps, 100Mbps, 1Gbps
  • Onboard - Motherboard Onboard or Add-On
  • Brands - Intel, Asus, D-Link, Realteck, StarTech
  • Usage: Basic: 10Mbps (ethernet), Normal: 100Mbps(Fast Ethernet), Advance: 1Gbps (Gigabit Ethernet)


Wifi Card

WIFI card Wifi cards are replacing wired ethernets. We are replacing the wired networks with wifi routers. So wifi network cards are becoming a treads in PC systems.

Buying Wifi card (factors and brands)

  • Bitrate - 56kbps is the default for dialup modem. ADSL modem can speed upto 1Mbps to 1000Mbps.
  • Wifi Band 802.11 a/b/g/n generation
  • Wifi distance range
  • Brands - Intel, Asus, TP-Link, D-Link, Realteck
  • Usage - Basic: Dialup, Normal: ADSL Broadband, Advance: ADSL Highspeed Broadband


Hub and Router

Hub A network hub or switch is a device which connects many network computers/hosts together. A router is a device which is connected between two different network subnets. Router or a all have a set of downstreap ethernet ports. All the computers in the same subnet should be connected to these ports. It will also have an uplink port. This port is used to connect to another network or to main network. A router will have a WAN port. This is often a ADSL telephone port.

Buying Network HUBs (factors and brands)

  • Ethernet speed 10Mbps, 100Mbps, 1Gbps
  • Number of ethernet ports.
  • Brands - Asus, TP-Link, D-Link
  • Usage - Basic: 10Mbps (ethernet), Normal: 100Mbps(Fast Ethernet), Advance: 1Gbps (Gigabit Ethernet)


Modem and ADSL Router

ADSL Modem is used to connect computer to the internet. Modems use telephone lines or ethernet to connect to the Internet service provider (ISP). Modem modulates the tone of the telephone sounds with the bit streams from computer and sends to the ISP. The signals from the ISP is again feed to Modem. Modem demodulates the tones or sound signals into bit streams and they are send to computer. Model Dialup modems are obsotite. We are in the era of broadband internet and ADSL modems and routers are used.

Buying Modem & ADSL router (factors and brands)

  • Bitrate - 56kbps is the default for dialup modem. ADSL modem can speed upto 1Mbps to 1000Mbps.
  • Wifi Band 802.11 a/b/g/n generation
  • Wifi distance range
  • Brands - Asus, TP-Link, Netgear, D-Link.
  • Usage - Basic: Dialup, Normal: ADSL Broadband, Advance: ADSL Highspeed Broadband


Multimedia speakers

Multimedia speakers A multimedia computer is made with speakers and microphones. Multimedia speakers will be a must when computer is used as personal entertainment device, video and audio editing device. A good quality speaks can turn the system into a mini home theater or a musical jukebox.

Buying Multimedia speakers (factors and brands)

  • Speakers and size
  • Sound reproduction.
  • Hifi sound and woofer
  • Brands - Creative, Logitech Z625. Philips Harman Kardon Soundsticks III. Zebronics
  • Usage - Normal/Basic: Basic speaker, Advanced: 5.1 sound speakers with woofer.


Headphones

Headphones Headphones are need for listening to sounds, audios, songs or listining to movies in the personal computer.

Buying Headphones (factors and brands)

  • Wired or Wireless
  • Sound reproduction.
  • Noise cancellation.
  • Hifi, Bass
  • Battery life
  • Brands - Bose, Sony Philips Audio Technica.
  • Usage - Normal/Basic: Wired Basic, Advanced: Bluetooth.


Microphones

Microphones Microphones are needed for a multimedia workstations. It is needed to record sounds, songs and converationas.

Buying Microphones (factors and brands)

  • Carbon sensor or coil base
  • Sound reproduction.
  • Noise cancellation.
  • Brands - Blue Yeti. Shure MV5. Audio-Technica AT2020USB+ Samson Go Mic. Samson Meteor Mic. Audio-Technica ATR2100x-USB. Blue Snowball. Fifine Cardioid Mic.
  • Usage - Normal/Basic: Basic Chatting, Advanced: speech, songs etc recording.


Webcam

Webcam Webcam is used for video chatting and conferencing. This is needed for personals who does frequent chat with people or business person who meet with their client verstually. This gadget can be plugged to USB port.

Buying Webcam (factors and brands)

  • Resolution - 720p, 1080P HD resoution or more.
  • Low light - performane at light and low light.
  • Picture quality - output picture quality.
  • Features - Photo taking features. Color / background tweaks.
  • Compatibility - Driver compatibility with Windows, MAC OX OS, Linux.
  • Brands - Logitech,Microsoft, Razer Kiyo, Mevo., Creative Labs.
  • Usage - Normal: None, Used only for chatting or video/photo shooting.


Joystick

Joystick Joystick is one type of pointing and controlling input device. Joystick has many click buttons, stick type controls which can be moved in different angles and directions. Joystick is one input device primarily used for gaming.

Buying Joystick (factors and brands)

  • Buttons - Number of controlling buttons.
  • Stick and sensors - Presence of two stick contols and other motion sensors.
  • Compatibility - Compatibility with Windows, MAC OX OSs, XBox, Playstation gamaing consoles.
  • Brands - Thrustmaster, Logitech, Mad Catz, Gladiator Joystick.
  • Usage - Normal: None, Used only for gaming