An Overview of Storage Devices - CompTIA A+ 220-801: 1.5

Hard disk drives

Tracks and cylinders

Solid-state drives (SSD)

Master Boot Record (MBR)

• The first sector of a hard drive 
• Usually only 512 bytes
• Contains:
• Table of primary partitions
• Disk signature
• Directions for starting the operating system

Optical formats

• Small bumps read with a laser beam
• Microscopic binary storage
• CD (Compact Disk)
• 700 megabytes (MB) capacity

• DVD (Digital Versatile Disc)
• 4.7 gigabytes (GB) for single layer
• 8.5 GB for dual-layer

• Blu-ray Disc
• 25 GB for single-layer
• 50 GB for dual-layer

Writing to optical media

• "Burners" don't create bumps
• They darken photosensitive dye
• Compact Disk-ReWritable  (CD-RW)
• DVD Read and Rewritable (DVD-R/RW)
• and Dual Layer (DVD-R DL)
• Blu-ray Disc Recordable (BD-R)
• Blu-ray Disc Recordable Erasable (BD-RE) 

Removable storage- flash memory

External hard drives

Tape drives

Installing and Configuring Expansion Cards - CompTIA A+ 220-801: 1.4

High-end video cards

Audio Expansion 

Television tuners

SCSI adapter  (Small Computer System Interface)

Serial / parallel adapter Expansion Card

USB card adapter

Modem

Ethernet adapter

Documentation

• Check the motherboard documentation
• Number and type of slots
• Check the adapter card documentation
• Minimum requirements
• Hardware, software
• Knowledge
• Any "gotchas?"

• Support forums
• What are the other people saying?
• You may need to perform a driver installation before installing hardware

Driver installation

• You checked the documentation first, right?
• Check the web for the latest version
• Uninstall previous drivers through Windows Device Manager
• Manufacturer provided setup program
• Manual installation through Windows Device Manager
• Check the Device Manager for the status
• Does it work?

Understanding PC Memory - CompTIA A+ 220-801: 1.3

Using memory

• CPU Registers
• Temporary storage
• Caches
• On die Static RAM (SRAM) caches
• External (off-die caches)

• DRAM
• Dynamic Random Access Memory
• Paging systems / Virtual memory

Memory transfer

• Bandwidth
• "Width" of the memory bus
• Bytes transferred with each clock cycle
• Memory bandwidth (8, 16, 32, 64 bits)
• Amount of information transferred
• Width of the memory module

• The number of physical chips on the memory module is irrelevant

Memory speed

• Synchronous DRAM (SDRAM)
• Synchronized to bus
• Memory speed identified as throughput in megabytes per second

• SDRAM measured in clock speed: 100 MHz bus= PC100 
• DDR, DDR2, and DDR3 measured in throughput
• 1,600 MB/sec = PC-1600
• 3,200 MB/sec = PC-3200
• 6,400 MB/sec = PC-6400

 Memory latency

• CAS
• Column Address Strobe
• Column Address Select
• CAS Latency (CL)
• Clock cycles between a memory request sent and data received
• The lower the CL number, the fewer clock cycles and faster the data transfer
• A DDR2 667 MHz CL=4 is faster than a DDR2 667 MHz CL=5

Memory that checks itself

• Used on critical computer systems
• Parity memory
• Additional parity bit
• Won't always detect an error
• Can't correct an error
• Error Correcting Code (ECC)
• Detects errors
• Corrects on the fly
• Not all systems use ECC
• It looks the same as non- ECC memory

Multi-channel memory 

• Installed in pairs or trios for maximum throughput
• Memory combinations should match
• Exact matches are best
• Memory module slots are often colored

Single-sided vs double-sided memory 

• Does not refer to the pysical layout of the memory package
• Ranks
• The "groups" of memory on a module that can be independently accessed
• Memory controller moves between the ranks
• Also called "sides"
• May be called "rows" in older documentation

Memory ranks

•  From the Intel 875P Chipset Memory Configuration Guide
• 1 Rank is single-sided DIMM
• 2 Ranks is a double-sided DIMM
• Check the motherboard documentation to ensure the correct memory

An Overview of PC Memory Types - CompTIA A+ 220-801: 1.3

What is memory?

• Random Access Memory (RAM) is the most common
• But it's not the only kind of memory

• Memory is not hard drive storage
• Don't mix the two terms
• Data is stored permanently on the hard drive

• Data and programs can only be used when moved to RAM

Read Only Memory (ROM)

• Can't be changed or erased
• A good place for a BIOS
• PROM
• Programmable ROM
• Write once

• EPROM
• Erasable PROM
• Write/Erase/Write again

• EEPROM
• Electronically Eraseable PROM
• Flash memory

Static RAM (SRAM)

• Very fast memory
• Very expensive memory
  

Dynamic Random Access Memory (DRAM)

• The RAM we know and love
• Dynamic= Needs constant refreshing
• Without refreshing, the data in memory disappears.

Synchronous DRAM (SDRAM)

• Don't confuse SDRAM with Static RAM (SRAM)
• SDRAM is synchronous with the common system clock
• 133 Mhz clock = PC133

Rambus DRAM (RDRAM)

• Introduced with the 400 MHz FSB Pentium 4
• Licensed by Rambus, Inc
• Rambus and Intel partnership

• Relatively expensive compared to SDRAM

Double Data Rate (DDR) SDRAM

•  Twice the data rate as "ordinary" SDRAM

Double Data Rate 2 (DDR2) SDRAM

• Enhanced electrical interface, buffers, off-chip drivers

Double Data Rate 3 (DDR3) SDRAM

• Twice the data rate of DDR2, larger chip capacities

It won't fit!
You can not use different types of DDR memory on different motherboards. Motherboard is designed for DDR, DDR2, DDR3, not interchangeable.

Motherboard Jumpers and Connectors - CompTIA A+ 220-801: 1.2

Motherboard Chipsets - CompTIA A+ 220-801: 1.2

Motherboards/ System boards

• Everything begins or ends on the motherboard
• Sometimes called the mobo
• Standard Sizes
• Constant change
• Chipsets
• Bus speeds
• Cooling methods

Motherboard chipset diagram

 Northbridge (memory controller hub) 

• Connects the CPU to memory and high-speed graphics card
• Modern computers include cooling options
• Heatsink
• Fans

 Southbridge

• Manages connections
• PCI interface slots
• USB, Ethernet, IDE, ect
• Onboard graphics controllers
• BIOS

The chipset evolution

• Nothing stays the same
• It's all about speed

• More functions are moving into the CPU
• Bigger, faster, stronger

•  Intel Sandy Bridge processors
• Processor cores
• Memory controller
• Graphics processing unit (GPU)

CPU Sockets - CompTIA A+ 220-801: 1.2

Dual In-line Package (DIP)

Obsolete Intel 8088 Dual In Line Package

Single Edge Contact Cartridge (SECC)

Pin Grid Array (PGA)

Zero insertion Force (ZIF) sockets

Land Grid Array (LGA) Commonly used today

• Reverse the PGA
• Pins are on the motherboard
• No pin to damage on the CPU
• Easier to damage the motherboard

• Found on many different processors
• Intel Pentium 4, AMD Opteron, Intel Sandy Bridge (i3, i5, i7)

Motherboard RAM Slots - CompTIA A+ 220-801: 1.2

Memory Slots

• Memory types have changed through the years
• Driven by standardization and technology
• One of the most important components of your computer
• Speed, speed, speed
• Every motherboard is different
• Check your documentation

SIMM ( Single In line Memory Module )

• Single In-line Memory Module
• No longer used
• 30 pin and 72 pin
• Not all SIMMs follow the standard
  

 RIMM ( Rambus Inline Memory Module )

• 16 bit (184 pins) and 32-bit (232 pins) modules
• Contains Rambus Dynamic Random Access Memory ( RDRAM )
• Every memory slot must be filled
• 16 bit modules require a Continuity RIMM (C-RIMM)
• 32 bit modules require a Continuity and Termination RIMM (CT-RIMM)

DIMM ( Dual inline memory module ) - Most Common Today 

• Dual inline memory module
• electrical contacts are different on each side
• 64 bit data width
• Package used for SDRAM (168 pins), DDR (184 pins), and DDR2/DDR3 (240 pins)

SO-DIMM ( Small Outline Dual In-line Memory Module )

• 68mm x 32mm
• 72 pin, 100-pin, 144-pin, 200-pin and 204- pin versions
• Used mostly in laptops and mobile devices

Motherboard Expansion Slots and Bus Speeds - CompTIA A+ 220-801: 1.2

Bus architecture

• A Communication Path
• A city of technology
• Internal PC Growth
• Independent pathways
• System expansion
• additional capabilities 

The expansion bus

• "Width" in bits
• Big roads, little roads
• Width is changing to bandwidth

•  Clock speed of bus
• The expansion bus gets its own clock
• 1 MHz (megahertz) = 1 million cycles per second
• 1 GHz = 1000 MHz
• Clock speed does not necessarily equal transfer rate 
• DDR3 SDRAM can transfer 64 times the memory clock speed

Conventional PCI (Peripheral Component Interconnect)

• Created in 1994
• A common expansion interface
• 32-bit and 64-bit bus width
• Throughput varies by bus version
• 133 MB/s (32-bit at 33 MHz)
• 266 MB/s (32-bit at 66 MHz or 64-bit at 33 MHz
• 533 MB/s (64-bit at 66 Mhz)

 PCI 32-bit expansion card

PCI 64-bit expansion card

Mini PCI

• PCI for laptops
• Shrink it down for mobile use.
• Expand features of laptops
• Wifi, mobile broadband, etc

•  No access to the card
• It's inside the laptop
• Can't touch it

PCI-X (PCI eXtended)

• Designed for servers
• Higher Bandwidth
•  Four times the clock speed
• Built to handle higher speed, network, and storage
• 1,064 MB/s capacity
• THIS IS NOT PCI EXPRES (completely different)

PCI Express

• Also known as PCIe
• This is not (PCI-X)
• Not really a bus in the traditional sense
• Unidirectional serial "lanes"
• Slower devices don't slow down everyone
• One,two,four,eight,sixteen, or thirty-two full duplex lanes
• x1, x2, x4, x8, x16, x32
• "x" is pronounced "by"
• i.e., "by 4," "by 16"

PCI Express throughout

• Different versions of PCIe
• Improvement in speed with each iteration
• Per-lane throughput in each direction
• -v1.x: 250 MB/s
• -v2.x: 500 MB/s
• v3.0: 985 MB/s (8 GT/s)
• v4.0: 1969 MB/s (16 GT/s)

CNR ( Communications and Networking Riser)

•  Modular riser for networking, modem, audio, etc.

AGP ( Accelerated Graphics Port)

•  Almost always called AGP
• Designed to cover the gap between PCI and PCI Express
• Difficult to find AGP today

AGP Versions

• AGP 1x (266MB/s),
• AGP 2x (522MB/s)
• AGP 1.0, 3.3V
• AGP 4x (1.07 GB/s)
• AGP 2.0, 1.5v
• AGP 8x (2.1 GB/s)
• AGP 3.0, 0.8V