Memory Address

Page Memory

- Memory is divided into equally-sized blocks called pages. An address is then broken down into a page number and the byte position on that page. - Associates a page with a specific task - Memory-management schemes - In the paging memory-management scheme, the operating system retrieves data from secondary storage in same-size blocks called pages. - Java uses page model

Hows is the memory Address implemented?

A number that is assigned to each byte in a computer's memory that the CPU uses to track where data and instructions are stored in RAM.

What is paging?

Grouping of information (physical address and logical blocks)

How does the CPU communicate with the RAM?

The computer's CPU uses the address bus to communicate which memory address it wants to access

How does the memory interpret the memory address?

The memory controller reads the address and then puts the data stored in that memory address back onto the address or data bus for the CPU to use

What is a memory address?

The orderly arrangement of data is called addressing of memory.

X86 Segmented Memory

Very similar to page memory (C programming language takes advantage of this)

What is a word?

Word = 16 bits or 2 bytes

Virtual Address/Logical Memory

An address that is logically adjacent to one another that work on the computing side. It accesses the page table that references the physical memory

Physical Memory/Physical Address

Not stored logically adjacent to one another. The physical location where the data is stored (Instructions in RAM that needs to be decoded. After it has been decoded, it is used to determine where the exact memory is stored in RAM and where to copy it into the register)

Flat memory model/linear memory model

Refers to a memory addressing concept in low-level software design such that the CPU can directly (and sequentially/linearly) address all of the available memory locations.

PROS and CONS of Flat memory

• Simple interface for programmers, clean design • Greatest flexibility • Minimum hardware and CPU real estate for simple controller applications • Maximum execution speed • Not suitable for general computing or multitasking operating systems, unless enhanced with additional memory management hardware/software • Linux uses a Flat Memory model

Pros/Cons of Page Memory

• Suitable for multitasking, general operating system design, resource protection and allocation • Suitable for virtual memory implementation • More CPU real estate, somewhat lower speed • More complex to program • Rigid page boundaries, not always the most memory efficient