# How do I calculate virtual memory size?

## How do I calculate virtual memory size?

Page Table Size = number of page entries in page table X size of one page entry. Let’s consider an example, Virtual Address Space = 2 GB = 2 X 2 ^ 30 Bytes. Page Size = 2 KB = 2 X 2 ^ 10 Bytes.

What is the size of a page table for a process that has 256K of memory starting at address 0?

In the following questions, sizes are in bytes. What is the size of the page tables for a process that has 256K of memory starting at address 0? Assume each page-table entry is 2 bytes. But the actual answer is 4608 bytes.

How much memory space is needed for the user page table?

The page table needs one entry per page. Assuming a 4GB (2^32 byte) virtual and physical address space and a page size of 4kB (2^12 bytes), we see that the the 2^32 byte address space must be split into 2^20 pages. This means the page table must have 2^20 entries.

### What is page size in virtual memory?

The idea behind virtual memory is that physical memory is divided into fixed size pages. Pages are typically 512 to 8192 bytes, with 4096 being a typical value.

How do you determine the size of a virtual address?

Virtual address space is 2 to the number of bits in the virtual address. So 224 = 16 megabytes.

Can a page table be designed as virtual memory?

A page table is the data structure used by a virtual memory system in a computer operating system to store the mapping between virtual addresses and physical addresses. The page table is a key component of virtual address translation which is necessary to access data in memory.

#### How many bits are required for each page table entry?

So, each entry is at least 44 bits (6 bytes for byte-aligned, 8 bytes for word-aligned). Each top-level page table is therefore 256*6 = 1536 bytes (256 * 8 = 2048 bytes).

How many pages is virtual address space?

There must be one page table entry for each page, so there are 8192 entries in the page table. Suppose each entry in a page table takes 45 bytes. The virtual address space is 1024 pages.

What is the size of page table entry?

Both can have different sizes, but page table sizes are most commonly 4096 kb or 4 mb and page table size is increased by adding more entries. 1) Because 4 bytes (32 bits) is exactly the right amount of space to hold any address in a 32-bit address space. 2) Because 1 million entries of 4 bytes each makes 4MB.

## What are the 7 memory modules?

Some standard module types are:

• DRAM chip (Integrated Circuit or IC) Dual in-line Package (DIP/DIL) Zig-zag in-line package (ZIP)
• DRAM (memory) modules. Single In-line Pin Package (SIPP) Single In-line Memory Module (SIMM)
• Stacked vs. non-stacked RAM modules.

What is the difference between a virtual page and a page frame?

A page (or memory page, or virtual page, or logical page) is a fixed-length contiguous block of virtual memory. A frame (or memory frame, or physical page, or page frame) is a fixed-length block of RAM (ie. physical memory, it exists – as in “physical”.

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