Motherboards/Processors/Memory

Processors (CPU)

Terminology

• Clock speed is the rate the processor executes instructions. (the faster the better usually)
• Arithmetic Logic Unit (ALU) is the part of the CPU that processes data.
• Cache memory (L1 or L2) is a very high-speed block of SRAM that interacts between the CPU and system RAM. (Usually, the more the better). Pentium processors use branch prediction
• Data bus refers to the wires (lines) that carry data to and from the processor (and cache, and RAM) (The wider the better, usually)
• Address bus refers to the wires (lines) that carry specific addresses to and from the processor. (The wider the bus, the more addresses that can be sent simultaneously)
• Register size refers the size of the temporary storage areas that hold data before and after processing by the ALU. This also determines software compatibility: Windows 2000 instructions are 32-bit, so it cannot run on a 16-bit processor.
• Multitasking is either pre-emptive or cooperative. Pre-emptive multitasking is controlled by the OS, which divides processor time accordingly. Cooperative multitasking is performed by the applications themselves
• Multiprocessing, which usually increases system performance, takes place simply whenever a system has more than one processor. Asymmetric multiprocessing allocates specific tasks and applications to specific processors. Symmetric multiprocessing (SMP) tasks and applications run off any processor (further increases performance).
• Real Mode is a processor mode where addressable memory (RAM) is seen as linear storage location that cannot be divided into sections, nor allocated to specific (ie, memory-intensive) programs. It cannot run Windows (no multitasking), only DOS.
• Protected Mode, introduced with the 286, allocates specific amounts/sections of memory to applications, multitasks, and supports virtual memory. All major OS use protected mode. Virtual Real Mode (or enhanced Protected Mode) emulates real mode from within protected mode to run DOS applications under Windows.

Pentium Processors

• Introduced in 1992
• 32-bit address bus
• 32-bit registers
• 64-bit data bus
• Built-in math-coprocessor
• PCI (Peripheral Component Interconnect) bus compatibility

Generation	Clock Speeds	L2 Cache	Register size	Data bus width	Addressable memory
Pentium I	60-66 90-100 120-166	16 KB	32-bit	64-bit	4 GB
MMX	166-233	32 KB	32-bit	64-bit	4 GB
Pro/P6 (RISC)	120-200	16 KB	64-bit	64-bit	4 GB
Pentium II (SEC)	233-450	512 KB	64-bit	64-bit	4 GB
Celeron	500-800	0-128K	64-bit	64-bit	4 GB
II Xeon	400-450	512KB-2MB	64-bit	64-bit	4 GB
III	450-1GHz	256KB	64-bit	64-bit	4 GB
III Xeon	500- 1GHz	256KB- 2MB	64-bit	64-bit	4 GB
Itanium (EPIC)	-1 GHz	L2 onchip L3 - 4 MB	64-bit	64-bit	16 GB
IV	1.4-1.5GHz	256 KB	?	accel. 64-bit	?

Check out Webopedia’s Processor Guide

Processor Sockets

• Socket 3: 486DX, AMD 5x86, Cyrix 5x86, Pentium OverDrive 63/83
• Socket 4: Pentium 60/66, Pentium OverDrive 120/133
• Socket 5: Pentium 75-133, Overdrive 125-166, MMX 125-166
• Socket 7: Pentium 75-200, Overdrive, MMX, K5, K6, 6x86MX
• Socket 8: Pentium Pro
• Slot 1: Pentium II, Pentium Pro
• Slot 2: Pentium II, Xeon

Non-Intel Processors

• AMD
• Cyrix

Generation	Clock Speeds	L2 Cache
K6 II	500-550	0
K6 III	400-450	256
Athlon	850-1.2 GHz	256
Duron	700-800	64

See also:

Intel website

AMD website

Memory

Terminology

• Memory speed: measured in nanoseconds, this is the time to access data that is stored in memory (50-80 ns)
• Parity: a simple error-checking method where each data byte includes a ninth bit called the parity bit (even/odd = 1/0).
• ECC: Error Checking and Correcting is a kind of enhanced memory checking that detects memory errors, but cannot correct them. Will halt the system
• Memory Banks: installed memory must fill a bank. Old systems required two 72-pin SIMMs, present systems only need one DIMM

ROM

• Read-Only Memory (non-volatile)
• Typically stores low-level hardware instructions (BIOS)

RAM

• Random-Access Memory (volatile)
• The processor’s workspace
• Temporarily stores data (as long as constant power is being supplied)
• DRAM (Dynamic RAM)
• SRAM (Static RAM)
• Video RAM types: VRAM (Video RAM), WRAM (Windows RAM), SGRAM (Synchronous Graphics RAM)

DRAM

• Main system memory (DIMM, SIMM)
• High-density memory modules
• Stores data while programs are running (OS, applications, etc)
• Fast Page Mode DRAM
• Extended Data Output (EDO) DRAM
• Burst Extended Data Output (BEDO) DRAM
• Synchronous DRAM, or SDRAM

SRAM

• Faster than DRAM (4 times faster)
• Larger, more expensive
• Used for speed-critical functions, like cache

VRAM

• Video RAM (all though all types of Video RAM are sometimes called this generically)
• AKA Dual-port RAM
• For high-performance video adapter cards
• Two data ports: one read, one write

WRAM

• Windows RAM
• Dual ported
• Slightly faster than VRAM (25% faster)

SGRAM

• Synchronous Graphics RAM
• Synchronized with the system clock
• Single-ported

Memory Packages

• DIPP: Dual in-line Pin Packages (EEPROM)
• SIPP: Single in-line Pin Packages
• SIMM: Single in-line Memory Modules (older system RAM, 30 or 72 pin)
• DIMM: Dual in-line Memory Modules (typical system RAM, 168 pin)
• SODIMM: Small Outline DIMMS (typical Laptop/PDA/IMac system RAM, 144 pin)

See also:

The Ultimate Memory Guide

PCTechGuide on Memory

Motherboards

Motherboards are the foundation for every PC. You should be very familiar with system board architecture and be able to recognize most components. Components to be able to identify include:

• CPU
• Real-time Clock and CMOS battery
• BIOS chip
• Switch connectors
• Cache
• IDE and floppy connectors
• All expansion slots and types
• Memory banks and types
• Power connectors
• All integrated ports, including video (AGP)

Terminology

• System Chipset: the logic circuits for system functions like caching and interrupting. The chipset will affect the processor type, speed and multitasking, the amount of RAM and L2 cache supported, and power management.
• Controller Chips: Keyboard and PS/2 mouse controllers, I/O port controllers, EIDE and floppy drive controllers, and any other built-in interfaces (like sound, network)
• Clock: Handles multiple speeds with the clock multiplier
• I/O Ports: usually 2 serial, 1 parallel, 2 USB, 2 PS/2 (keybd, mouse), 2 internal EIDE, 1 internal floppy port
• Memory Slots: SIMM or DIMM, or both
• Level 2 Cache: usually a DIP chip or COASt (Cache on a stick), a dedicated high-speed backside bus (DIB – Dual Independent Bus) architecture.
• Form Factors: the shape and physical size of the system board: AT, baby AT, ATX, mini ATX, LPX, and mini-LPX, NLX.
• Bus: buses are a common medium for the transfer of data from one location, device, or component to another.

PCTechGuide Motherboards (great graphics)

Hardware Central’s Tutorial

Buses:

• Processor Bus
• Memory Bus
• Cache Bus
• I/O Bus
• Expansion Bus

Bus Speeds

Device	Clock	Speed, e.g.
CPU	System clock x 4	266 MHz
L2 Cache	System clock x 2	133 MHz
System Memory		66 MHz
PCI bus	System clock x 2	33 MHz
ISA bus	PCI bus x 4	8.3 MHz

See also:

A Guide to the PC Bus Ride

Printers

Types

• Dot Matrix
• Inkjet
• Laser (and LED)

Dot Matrix

• Also called Impact printers (parts actually impact the paper)
• Fires pins (or print wires) at an ink ribbon, which contacts the paper and leaves a mark
• The print head, the assembly which contains the pins, moves left to right across the paper, line by line, creating letters out of the circular dots of ink that have impacted he paper.
• Coils of wires called solenoids are energized, thus creating an electromagnet, and cause the pins to shoot forward and strike the ribbon.
• Print quality is measured in "pins", as in 9-pin, 24-pin, 48-pin printers: number of pins in the print head.
• The quality of print is at best NLQ, Near Letter Quality.
• The speed of the printer is measured in cps, characters per second.
• The paper most often used with dot matrix is continuous, tractor-fed paper with perforated strips on the sides.
• This printer uses pin feeders and tractor feeders with this paper to prevent skewing. The roller (or platen) applies pressure (friction) when you use plain paper to keep the paper from slipping. If you are using multiple-copy paper, you can adjust the platen gap to the thickness of the paper.
• Dot matrix printers are rather expensive to purchase now because they serve the niche multiple-copy stationary market, and so many companies want old ones fixed.

Inkjet Printers

• Inkjet printers use liquid ink-filled cartridges that force out and spray ink at the page through tiny holes called nozzles.
• The printer sprays ink at the page through pressure and electricity. Normally, the pressure inside the ink cartridge (in the ink reservoir) is a bit less than pressure outside. When the deflection plates are electrically charged, ink is forced out.
• Inkjet printers have two kinds of print heads that move back and forth in perfect synchronization with the spray of ink. HPs have thermal-shock print heads, which have a heating element around each nozzle that, when heated, causes the ink to expand. Epson printers have piezoelectric (electrostatic) print heads that, when charged, changes the size and shape of the nozzle, and acts like a pump.
• Inkjet printers can use plain paper and inkjet specific paper (for higher print quality).
• Print quality is measured in dpi, dots per inch.
• Print speed is measured in ppm, pages per minute.

Laser Printers

The majority of businesses (including BrainBuzz here) use laser printers for demanding printing needs (speed, quantity, quality).

• Laser printers print one whole page at a time, and require RAM (more memory) to operate.
• Print quality is measured as dpi
• When the printer receives the print data for a page, it breaks the data into single-dot strips called rasters (this is called rasterizing, amazingly enough).

The Laser Printing Process:

1. Electrostatic Charging (Conditioning)
2. Imaging (Writing or Exposing)
3. Developing
4. Transferring
5. Fusing
6. Cleaning

See also:

How Printers Work

PCTechGuide’s Laser Printers (excellent graphics)

Printer Connections and Configurations

To install a printer in Windows 9x/NT/2000, go to Setting => Printers => Add Printer and walk through the Print Wizard.

Connections

• Parallel (local)
• Serial (local)
• Network

More resources:

How to share a local printer

Troubleshooting Printers

• Printer not working: switched on, plugged in, online, check cables
• Paper jam: cheap paper, wrong type, stored improperly, loaded improperly
• Output corruption: printer driver, check setup
• Poor quality: toner/ribbon low, cheap/wrong paper
• Laser memory errors: not enough RAM
• Blank pages: OPC drum, corona wire improperly seated.

Networking Concepts

Introduction to Networking

• A network is two or more computers connected that share data.
• Networking on the Internet is called internetworking.

LAN

• Local Area Network
• Single site within a building
• Sharing resources and information (files, peripherals, storage, software)
• Communications: Ethernet and CSMA/CD

WAN

• Wide Area Network
• Multiple sites across a large geographic area
• Sharing resources and information (printing, files)
• Access: dial-up using modem, ISDN, DSL, cable, leased lines

How a Network Works

Networks are made up of three basic components:

• Protocols – rules of communication
• Transmission media – methods for interconnecting network elements
• Network Services – shared resources

Networks are either peer-to-peer or server-based.

Peer-to-peer:

• Doesn’t require dedicated resources: any host can share its resources with any other host on the network
• Less expensive, easier to work/maintain, less secure, fewer users (less than 10)
• File system management problems
• Windows for Workgroups 3.x/95/98

Server-based:

• Configuration of nodes. A dedicated node that shares out its resources to hosts is a server (resources like printers, files, and applications)
• More security, more expensive
• Print servers, file servers, mail servers, web servers
• Novell NetWare, UNIX, Microsoft NT/2000, Apple AppleTalk

Physical Topologies:

Bus	Star	Ring

Mesh: every computer is connected to every other computer
Hybrid: any of these in combination
Token Ring: (or star-wired ring) uses a MAU and token passing to ensure only one device is communicating at a time (FDDI uses token passing)

Do not confuse Physical Topologies with Logical Topologies.

Logical Topology: the actual path of a signal over a network (bus, ring)

Physical topologies: how the network devices are actually connected.

Network Operating Systems:

• Novell NetWare 5
• Microsoft NT, 2000
• UNIX

Networking Components

• NIC (Network Interface Card), also called an adapter card: interface between a single computer and the network
• Repeater: an amplifier that prevents signal degradation over distance
• Hub: a focal point of a network – connects computers in a physical star topology
• Switches: device for filtering frames and connecting segments of a network, uses MAC addresses
• Routers: direct data packets between networks using IP addresses
• Brouters: combination bridge and router
• Bridges: directs information flow on a network from one node to another.
• Gateway: converts protocols
• Modem (Modulate/Demodulate): a device to connect computers over analog telephone lines.

Cables

• Fiber Optic cables are the fastest, most expensive, and most difficult to implement
  • Single-mode: specific wavelength
  • Multi-mode: many wavelengths (frequencies, or modes)
• Twisted Pair cannot exceed 100 m
  • STP: shielded twisted pair
  • UTP: unshielded twisted pair

Category	Description
1	Voice (UTP only)
2	4 twisted pairs, data transmission up to 4 Mbps (UTP only), token ring
3	4 twisted pairs, data transmission up to 10 Mbps, Ethernet
4	4 twisted pairs, data transmission up to 16 Mbps, token ring
5	4 twisted pair, data transmission up to 100 Mbps, Ethernet and fast Ethernet
6	4 twisted pair, data transmission up to 155 Mbps, fast Ethernet
7	4 twisted pair, data transmission up to 1000 Mbps, gigabit Ethernet

Connectors

• RJ-45 (like phone jack)
• Coaxial/BNC (Thicknet, Thinnet) (like cable TV)

Transmission Types

• Synchronous: transmissions are synchronized between the access devices and the network device (message-framed data), and the message is received in the order it was transmitted.
• Asynchronous: transmissions are asynchronized between the access device and the network device, but each character is synchronized by information in the header and trailer bits.
• Data transmission flow: circuits are:
  • Simplex: one direction
  • Half duplex: two directions, only one at a time
  • Full duplex: two directions simultaneously.
• Baseband: entire media bandwidth for a single channel using TDM (Time Division Multiplexing)
• Broadband: divides media bandwidth into multiple channels, each with a separate signal using FDM (Frequency Division Multiplexing)

Networking Issues

• Slowdown
• Bandwidth
• Cost
• Maintenance
• Traffic demands
• Hardware

Install and configuring a NIC

Network Interface Cards move data between a local computer and the network.

Types of NICs include:

• ISA
• PCI
• PCMCIA

Note: know how to install and configure a NIC, and also how to share resources.

Shared Folder	Shared Drive	Mapped Drive

Special Thanks to Cherina Sparks MA, A+ for contributing this Cramsession. Visit her site at http://debaucherina.stormloader.com