section 1 - components of a computer system Flashcards
Embedded systems
- embedded Systems are computers built into other devices, like dishwashers, microwaves and washing machines - It’s used when the bigger machine has a restricted set of instructions that are unlikely to change.
CPU
Processes all the data and instructions required to make the system work. Central Processing unit
CPU - Clock speed
This is the number of instructions a single processor core can carry out per second (Hz). For most desktop computers, this will be somewhere around 3.5 GHz (3.5 billion instructions per second). .The higher the clock speed, the greater the number of instructions that can be carried out per second.
Some CPUs can be overclocked to make them run at a higher clock speed than the factory-set rate. But it’s risky if not done properly - it can make CPUs overheat, causing crashes or permanent damage to the system. High performance cooling systems (e.g. water cooling) are usually needed.
CPU - number of cores
Each core in a CPU can process data independently of the rest. * The more cores a CPU has, the more instructions it can carry out at once, so the faster it can process a batch of data.
* Most PCs and smartphones have 4 or more cores these days.
CPU - cache size
- The cache is data storage inside the CPU that’s much faster than RAM. * A larger CPU cache gives the CPU faster access to more data it needs to process.
More RAM can mean a Faster or Smoother System
1) If a computer has too little RAM it may run slowly due to the use of virtual memory
2) The more RAM, the more applications, or more memory-intensive applications it can smoothly run, making it faster overall.
3) It’s easy to upgrade RAM on a PC or laptop - it’s just a matter of replacing the RAM sticks with higher capacity (or higher speed) ones.
4) If the computer already has plenty of RAM to run everything the user wants, increasing RAM may make no difference to performance.
GPUS help CPUs process Images.
1) GPUs (graphics processing units) are specialised circuits for handling graphics and image processing. They relieve the processing load on the CPU, freeing it to do other things.
2) Computers have basic GPUs integrated onto the motherboard or the CPU. For better graphics performance, a dedicated GPU (graphics card) is often used.
3) Using high-end graphics cards can greatly improve performance in graphics-intensive applications, e.g., PC gaming and design software.
Volatile memory
Volatile memory is temporary memory. It requires power to retain its data.
Non-volatile
Non-volatile is permanent memory it keeps its contents even when it has no power.
RAM
RAM is High Speed, read, write, Volatile memory.
1) RAM (or Random Access Memory) is volatile memory with fast access speeds
2) contains all data, files and programs, and the OS while they’re being used.
3) When a computer boots up, the operating system is copied from secondary storage to RAM.
virtual memory
Virtual memory is the use of secondary storage as extra RAM when the ram is full.
much slower than RAM
When RAM is full, the computer moves data that hasn’t been used recently to a location on secondary storage which is known as virtual memory.
If the CPU needs to read data stored in virtual memory, it must move the data back to RAM. This is slow as data transfer rates are much slower on secondary storage than RAM.
ROM
1) ROM (Read Only Memory’) is non-volatile memory.
2) ROM comes on a small, factory-made chip built into the motherboard.
3) It contains all the instructions a computer needs to properly operate. These instructions include the BIOS (Basic Input Output System), POST (Power on Systems Test) and the bootstrap.
4) As soon as the computer is powered on, the CPU reads the instructions from ROM. This tells the CPU to perform self-checks and set up the computer, e.g., test the memory is working OK, see what hardware is present and copy the operating system from secondary storage into RAM.
3 types of storage
- Primary storage
- Secondary storage
- Tertiary storage
Primary storage
Primary storage refers to the memory areas that the CPU can access very quickly, like CPU registers, cache, ROM and RAM. Primary storage has the fastest read/write speeds and is mostly volatile
Secondary storage
Secondary storage is non-volatile-it’s where all data (operating systems, applications, and user files) are stored when not in use. It includes magnetic hard disk drives, solid state drives, CDs, and SD cards. Read/write speeds are much slower compared to primary storage.
Summary of relative speeds cost and capacities of all these different types of storage
Defragmentation Utilities software
1) Files are stored on a hard disk in available spaces. Ideally, entire files would be stored together.
2) However, as files are moved, deleted, and change size, lots of small gaps begin to appear on the disk. When writing files to the disk, the OS splits files into smaller blocks to fill up the gaps.
3) Over time, the disk becomes more and more fragmented. This makes reading and writing files slower as the read/write head must move back and forth across the disk.
4) Defragmentation software reorganises data on the hard drive to put fragmented files back together. It also moves files to collect all the free space together. This helps to prevent further fragmentation.
5) As SSDs use flash storage with no moving parts, fragmentation doesn’t cause them any problems - they can access data just as quickly however it’s arranged. In fact, as SSDs have a limited number of read/writes, defragmenting them can actually shorten their lifespan.
