Virtualization and Optimization

Learning objectives:

• explain the differences between RAM and ROM memory

• explain the purpose of virtual memory and cache memory

Repeat

What is “virtualization”?

Repeat

What is “virtualization”? What is “virtualization machine”?

Repeat

What is “virtualization”? What is “virtualization machine”? What are some of the stages of

development of computer technology?

Repeat

What is “virtualization”? What is “virtual machine”? What are some of the stages of

development of computer technology?

Why use a virtual machine? What determines the speed of the

computer?

Main memory - data store that can be directly addressed by the CPU

Main memory is used to store program instruction and data, using the System Bus to communicate with CPU. Main memory is often created using Random Access Memory (or RAM) or Read Only Memory (ROM). Modern computers will have gigabytes of RAM, meaning that large programs can run and multiple programs can run at once. The more main memory that you have the larger the number of programs you can run at once.

RAM - Random Access Memory can be read from and written to. Data is cleared when the power is off.

ROM - Read Only Memory can only be read from, data is maintained when the power is off

The two main types of main memory are ROM and RAM. Whilst RAM might be several gigabytes in size, ROM will often be a few kilobytes. As ROM is read only memory, it tends to store core software instructions such as the code needed to load the Operating System into RAM (known as bootstrapping) or change the bios. RAM is much much larger and stores the code to run the operating system and programs that you run on your computer. When you load a disc into a games console, the code won't do anything until it has loaded from the disc into the system RAM, that's why you see a loading screen.

Give a definition for main memory:

Give a definition for main memory:

Main memory is a data store that can be directly addressed by the CPU

What is the difference between ROM and RAM?

What is the difference between ROM and RAM?

ROM is Read Only Memory, RAM is random access memory. This means that ROM cannot be written to, it can only be read from. RAM can be both read from and written to.

Name the four components of Von Neumann Architecture

Name the four components of Von Neumann Architecture

Processor Main memory I/O devices System bus

Cache - a memory with higher speed are designed for faster access to the data contained in the memory continuously at a lower speed access.

Кэш — это память с большей скоростью доступа, предназначенная для ускорения обращения к данным, содержащимся постоянно в памяти с меньшей скоростью доступа.

memory leak - утечка памяти

uncontrolled process of reducing the amount of free RAM or virtual memory computer associated with errors in the programs that are running on time does not relieve the unnecessary portions of memory already, with mistakes or system services control memory.

(процесс неконтролируемого уменьшения объёма свободной оперативной или виртуальной памяти компьютера, связанный с ошибками в работающих программах, вовремя не освобождающих ненужные уже участки памяти, или с ошибками системных служб контроля памяти.)

garbage collector – сборка мусора

garbage collection was invented by John McCarthy about in 1959

The program provides a means to automatically release the unused memory