UNIT 1 HARDWARE
1.1 MODULAR DESIGN
Modular design – computer you buy can be put together in pieces with personal
requirements in mind, instead of consisting of a single unit with fixed hardware
Smaller technologies are often less modular
Hardware parts are separate modules and are connected via the motherboard
using ports or slots
Simplifies the upgrading of computers
Advantage – it is simple to remove broken components and replace/upgrade
them with a new unit
USB, Firewire and Thunderbolt ports have replaced the need to have PCI slots for
many peripherals. Causing modern PC’s to have few PCI slots
1.2 FACTORS INFLUENCING THE PERFORMANCE OF A COMPUTER
1.2.1 CPU
CPU Speed
CPU affects computer’s speed, but does not achieve optimum performance in
isolation
Various other factors may diminish the gains of simply faster CPU speed
Overclocking
Per Component – CPU operates faster than system clock by changing its own
multiplication factor
The Whole System – system clock is increased affecting all components that
detect the system clock and multiply by a factor
Clock multiplication – process of multiplying the system clock by a factor
Operating voltages can be increased increases speed at which operation
remains stable
Overclocking can be dangerous:
o Components run at faster speeds they can become unstable or fail
o Increased power consumption more heat must be dispersed
To compensate for overclocking:
o Air cooling – through fans or piezoelectric pumps
o Other – liquids, heat sinks, phase change or undervolting
Register Size (32/64 bit)
64-bit doesn’t necessarily influence the speed, but 32-bit CPUs must process 64-
bit data in 2 stages, while 64-bit CPUs don’t
64-bit code may run slower due to its higher memory consumption, causing more
cache misses
Cache misses – failed attempts to read or write a piece of data in the cache
Hyperthreading
Allows one processor to appear to execute 2 threads at the same time by having
2 sets of registers on the CPU
o Each register set stores a different process to be executed by the CPU
, o When the CPU switches, the state of register must be saved to RAM and
the next state must be loaded from the RAM
o With hyperthreading, this is not needed, as both states are stored on the
CPU
In an OS, a hyperthreading CPU appears as 2 logical CPUs
Hyperthreading can improve performance, but must be supported by the OS
Main execution resource is the same as in a single core processor
o Enables 2 tasks to be executed at the same time, if only 1 task requires
the main execution resource
It does not always increase speed, but on average by 15%
Multiprocessing
Multiprocessing – to have multiple CPUs on a single CPU chip
o Processes can run at the same time, instead of appearing to do so
o Must be supported by the OS and motherboard
Looking at multiple processors in isolation is not a feasible way of assessing the
performance of a system; rather all factors should be considered
1.2.2 REGISTER AND DATA BUS
With a 32-bit register & a 32-bit address bus 232 memory addresses (± 4GB of
RAM)
With a 64-bit register & a 32-bit address bus 264 memory addresses (17.2
Billion GB of RAM)
The larger the data bus more data can be transferred to the CPU at one time
1.2.3 PRIMARY MEMORY: CACHE AND RAM
Amount of cache influences performance as it’s a high-speed SRAM located close
to, or in, the processor
Cache – allows content of RAM to be stored close to processor, hence the
processor checks here for next instruction before going to the RAM to check
More RAM means less virtual RAM is needed faster
1.2.4 ACCESS TO AND FROM SECONDARY STORAGE
Data transfer speed is dependent on 2 factors:
o Speed of bus technology
o Latency of the drive itself
Popular bus/drive combo is SATA:
o SATA I – SATA 1.5Gbps – bandwidth throughput is 150MB/s
o SATA II – SATA 3Gbps – bandwidth throughput is 300MB/s
o SATA III – SATA 6Gbps – bandwidth throughput is 600MB/s
USB Flash Drive – most popular form of solid-state persistent memory storage
due to its size and no need to have independent power source
o USB 1.0 – 12Mbps
o USB 2.0 – 480Mbps
o USB 3.1 – 5Gbps
o USB 3.2 – 10Gbps
1.2.5 SOLID STATE SPEED VS MECHANICAL DRIVE SPEED
1.1 MODULAR DESIGN
Modular design – computer you buy can be put together in pieces with personal
requirements in mind, instead of consisting of a single unit with fixed hardware
Smaller technologies are often less modular
Hardware parts are separate modules and are connected via the motherboard
using ports or slots
Simplifies the upgrading of computers
Advantage – it is simple to remove broken components and replace/upgrade
them with a new unit
USB, Firewire and Thunderbolt ports have replaced the need to have PCI slots for
many peripherals. Causing modern PC’s to have few PCI slots
1.2 FACTORS INFLUENCING THE PERFORMANCE OF A COMPUTER
1.2.1 CPU
CPU Speed
CPU affects computer’s speed, but does not achieve optimum performance in
isolation
Various other factors may diminish the gains of simply faster CPU speed
Overclocking
Per Component – CPU operates faster than system clock by changing its own
multiplication factor
The Whole System – system clock is increased affecting all components that
detect the system clock and multiply by a factor
Clock multiplication – process of multiplying the system clock by a factor
Operating voltages can be increased increases speed at which operation
remains stable
Overclocking can be dangerous:
o Components run at faster speeds they can become unstable or fail
o Increased power consumption more heat must be dispersed
To compensate for overclocking:
o Air cooling – through fans or piezoelectric pumps
o Other – liquids, heat sinks, phase change or undervolting
Register Size (32/64 bit)
64-bit doesn’t necessarily influence the speed, but 32-bit CPUs must process 64-
bit data in 2 stages, while 64-bit CPUs don’t
64-bit code may run slower due to its higher memory consumption, causing more
cache misses
Cache misses – failed attempts to read or write a piece of data in the cache
Hyperthreading
Allows one processor to appear to execute 2 threads at the same time by having
2 sets of registers on the CPU
o Each register set stores a different process to be executed by the CPU
, o When the CPU switches, the state of register must be saved to RAM and
the next state must be loaded from the RAM
o With hyperthreading, this is not needed, as both states are stored on the
CPU
In an OS, a hyperthreading CPU appears as 2 logical CPUs
Hyperthreading can improve performance, but must be supported by the OS
Main execution resource is the same as in a single core processor
o Enables 2 tasks to be executed at the same time, if only 1 task requires
the main execution resource
It does not always increase speed, but on average by 15%
Multiprocessing
Multiprocessing – to have multiple CPUs on a single CPU chip
o Processes can run at the same time, instead of appearing to do so
o Must be supported by the OS and motherboard
Looking at multiple processors in isolation is not a feasible way of assessing the
performance of a system; rather all factors should be considered
1.2.2 REGISTER AND DATA BUS
With a 32-bit register & a 32-bit address bus 232 memory addresses (± 4GB of
RAM)
With a 64-bit register & a 32-bit address bus 264 memory addresses (17.2
Billion GB of RAM)
The larger the data bus more data can be transferred to the CPU at one time
1.2.3 PRIMARY MEMORY: CACHE AND RAM
Amount of cache influences performance as it’s a high-speed SRAM located close
to, or in, the processor
Cache – allows content of RAM to be stored close to processor, hence the
processor checks here for next instruction before going to the RAM to check
More RAM means less virtual RAM is needed faster
1.2.4 ACCESS TO AND FROM SECONDARY STORAGE
Data transfer speed is dependent on 2 factors:
o Speed of bus technology
o Latency of the drive itself
Popular bus/drive combo is SATA:
o SATA I – SATA 1.5Gbps – bandwidth throughput is 150MB/s
o SATA II – SATA 3Gbps – bandwidth throughput is 300MB/s
o SATA III – SATA 6Gbps – bandwidth throughput is 600MB/s
USB Flash Drive – most popular form of solid-state persistent memory storage
due to its size and no need to have independent power source
o USB 1.0 – 12Mbps
o USB 2.0 – 480Mbps
o USB 3.1 – 5Gbps
o USB 3.2 – 10Gbps
1.2.5 SOLID STATE SPEED VS MECHANICAL DRIVE SPEED
