IT Foundations - D316 (CompTIA A+ Core 1)
Cert Master:
Module 3: Installing System Devices
Lesson 1: Power Supplies and Cooling:
Wattage Rating
● Power: rate at which energy is generated or used, measured in watts, calc as V x
Current (V*I)
● Types of power
○ DC (direct current): computers
■ VDC: volts of direct current
○ AC (alternating current): from the outlet
■ VAC
● PSU (power supply unit) must meet power requirements of PC components, with its
output capability measured in watts known as wattage rating
● Wattage rating
○ Measure of how much power can be supplied by PSU
○ Standard desktops 400-500 W
○ Enterprise and workstations sometimes 1000+ W
○ Gaming PCs 600+ W
○ CPU: 17-100+ W
● Underpowered PSU leads to:
○ System instability: random shutdowns, reboots, crashes. PSU struggles to supply
power to components
○ Component damage: overheating
● Example:
○ 300 W PSU operating at 75% efficiency draws 400W from outlet. Excess 100 W
lost as heat
● Modular power supply: power cables can be attached to ports on the unit as needed
● Redundant power: redundant PSUs needed for servers
● Heat sinks: fitted to components
○ Passive: memory modules
○ Active: CPUs, high end video cards, components that generate a lot of heat
● Liquid cooling:
○ Water block: attached directly to the CPU and transfers heat from the processor
to the coolant (liquid) that circulates through the system.
● ATX power supply: provides 3.3, 5, and 12 volt DC power sources
,Lesson 3.2: Storage Devices
RAID (redundant array of independent disks/devices)
● RAID levels represent different drive configurations with specific types of fault
tolerance, numbered from 0 to 6, with nested solutions like RAID 10 (RAID 1 + RAID 0).
● RAID can be implemented via software (software RAID) using OS features or via
hardware (hardware RAID) using a dedicated controller installed as an adapter card.
● Factors to consider when implementing RAID
○ Required fault tolerance
○ read/write performance
○ Capacity
○ Cost
○ Disks must be identical to avoid underutilization or performance bottlenecks
(smallest disk in the array would determine maximum usable space
● Disk striping: divides data into blocks and distributes them across all disks
○ Allows multiple disks to respond to requests in parallel
● RAID 0: no redundancy (only used for non critical cache storage)
●
● RAID 1: 2 disk mirrored drive. More expensive per GB than other fault tolerance because
it utilizes only 50% of the total disk space
,●
● RAID 5: striping + distributed parity.
○ Parity: instead of fully duplicating data like mirroring, parity stores small amounts
of extra data to recover information with lower capacity overhead.
○ Distributed parity: across 3+ drives. More drives = more risk. 1 drive fails = whole
system down
● RAID 10: combines features of RAID 0 and RAID 1.
○ Striped volume (RAID 0) made up of mirrored arrays (RAID 1).
○ Good fault tolerance: one disk in each mirror can fail without losing data
, ●
○ RAID 10 requires at least four disks and must have an even number of disks. It
has a 50% disk overhead due to mirroring.
● RAID 6 (striping with double parity)
○ Double parity: spreading two sets of parity info across all disks
○ Offers good read performance similar to RAID 5, but slower write performance
due to the need to calculate and write two sets of parity data. The array remains
operational even if one or two disks fail, though performance will degrade.
○ minimum of four disks is required, with two used for data storage and two for
parity.
○ Ex) four disk raid 6 with 1 TB disks has 2 TB of usable capacity
Storage devices
Lesson 3.3: RAM
Cert Master:
Module 3: Installing System Devices
Lesson 1: Power Supplies and Cooling:
Wattage Rating
● Power: rate at which energy is generated or used, measured in watts, calc as V x
Current (V*I)
● Types of power
○ DC (direct current): computers
■ VDC: volts of direct current
○ AC (alternating current): from the outlet
■ VAC
● PSU (power supply unit) must meet power requirements of PC components, with its
output capability measured in watts known as wattage rating
● Wattage rating
○ Measure of how much power can be supplied by PSU
○ Standard desktops 400-500 W
○ Enterprise and workstations sometimes 1000+ W
○ Gaming PCs 600+ W
○ CPU: 17-100+ W
● Underpowered PSU leads to:
○ System instability: random shutdowns, reboots, crashes. PSU struggles to supply
power to components
○ Component damage: overheating
● Example:
○ 300 W PSU operating at 75% efficiency draws 400W from outlet. Excess 100 W
lost as heat
● Modular power supply: power cables can be attached to ports on the unit as needed
● Redundant power: redundant PSUs needed for servers
● Heat sinks: fitted to components
○ Passive: memory modules
○ Active: CPUs, high end video cards, components that generate a lot of heat
● Liquid cooling:
○ Water block: attached directly to the CPU and transfers heat from the processor
to the coolant (liquid) that circulates through the system.
● ATX power supply: provides 3.3, 5, and 12 volt DC power sources
,Lesson 3.2: Storage Devices
RAID (redundant array of independent disks/devices)
● RAID levels represent different drive configurations with specific types of fault
tolerance, numbered from 0 to 6, with nested solutions like RAID 10 (RAID 1 + RAID 0).
● RAID can be implemented via software (software RAID) using OS features or via
hardware (hardware RAID) using a dedicated controller installed as an adapter card.
● Factors to consider when implementing RAID
○ Required fault tolerance
○ read/write performance
○ Capacity
○ Cost
○ Disks must be identical to avoid underutilization or performance bottlenecks
(smallest disk in the array would determine maximum usable space
● Disk striping: divides data into blocks and distributes them across all disks
○ Allows multiple disks to respond to requests in parallel
● RAID 0: no redundancy (only used for non critical cache storage)
●
● RAID 1: 2 disk mirrored drive. More expensive per GB than other fault tolerance because
it utilizes only 50% of the total disk space
,●
● RAID 5: striping + distributed parity.
○ Parity: instead of fully duplicating data like mirroring, parity stores small amounts
of extra data to recover information with lower capacity overhead.
○ Distributed parity: across 3+ drives. More drives = more risk. 1 drive fails = whole
system down
● RAID 10: combines features of RAID 0 and RAID 1.
○ Striped volume (RAID 0) made up of mirrored arrays (RAID 1).
○ Good fault tolerance: one disk in each mirror can fail without losing data
, ●
○ RAID 10 requires at least four disks and must have an even number of disks. It
has a 50% disk overhead due to mirroring.
● RAID 6 (striping with double parity)
○ Double parity: spreading two sets of parity info across all disks
○ Offers good read performance similar to RAID 5, but slower write performance
due to the need to calculate and write two sets of parity data. The array remains
operational even if one or two disks fail, though performance will degrade.
○ minimum of four disks is required, with two used for data storage and two for
parity.
○ Ex) four disk raid 6 with 1 TB disks has 2 TB of usable capacity
Storage devices
Lesson 3.3: RAM
