Page Size and Address Breakdown
Results appear here after pressing the calculate button.
| Field | Value | Meaning |
|---|
Calculate Page Size Computer Architecture
Use offset bits, page size, address bits, memory size, entry size, and TLB entries for detailed paging analysis.
Formula Used
The calculator uses binary memory formulas commonly used in paging problems.
Page Size = 2 ^ Offset Bits × Addressable Unit BytesOffset Bits = log2(Page Size / Addressable Unit Bytes)Virtual Pages = Virtual Address Space / Page SizePhysical Frames = Physical Memory / Page SizeVirtual Page Number Bits = Virtual Address Bits - Offset BitsFrame Number Bits = Physical Address Bits - Offset BitsSingle Level Page Table Size = Virtual Pages × PTE SizeProcess Page Table Size = Process Pages × PTE SizeTLB Reach = TLB Entries × Page SizeInternal Fragmentation = Process Pages × Page Size - Process Size
Example Data Table
| Virtual Bits | Physical Bits | Offset Bits | Page Size | Virtual Pages | Physical Frames | PTE Size | Single Level Table |
|---|---|---|---|---|---|---|---|
| 32 | 30 | 12 | 4 KiB | 1,048,576 | 262,144 | 4 bytes | 4 MiB |
| 36 | 32 | 13 | 8 KiB | 8,388,608 | 524,288 | 8 bytes | 64 MiB |
| 48 | 40 | 12 | 4 KiB | 68,719,476,736 | 268,435,456 | 8 bytes | 512 GiB |
How to Use This Calculator
- Select whether you want to calculate from offset bits or from a known page size.
- Enter virtual and physical address bits for the target architecture.
- Enter memory sizes only when your problem gives explicit memory capacity.
- Add process size, page table entry size, TLB entries, and table levels.
- Press calculate to view page size, table size, frames, pages, and reach.
- Use the CSV or PDF button to save the result for reports.
Page Size in Computer Architecture
Why Page Size Matters
Page size defines the block of memory moved between virtual memory and physical memory. It controls the number of offset bits in an address. A larger page gives fewer page table entries. It can also waste more internal space. A smaller page reduces waste. It may create larger tables and more lookups.
Address Fields
A virtual address is normally split into two parts. The low bits are the page offset. These bits choose a byte inside one page. The high bits identify the virtual page number. Physical addresses use the same offset length. Their high bits identify the frame number. This calculator shows each field clearly.
Table Size Planning
Page table size depends on virtual pages and entry size. A system with many virtual pages needs many entries. Each entry stores frame data, status bits, and protection flags. Multi level tables reduce allocated memory. They only create lower levels when a process needs them. The tool also estimates entries per table page.
Choosing Values
A good page size balances speed and memory cost. Very large pages improve sequential access. They reduce translation pressure and table growth. They may increase internal fragmentation. Very small pages fit mixed workloads well. They can raise page fault overhead. Use the comparison fields to test both choices quickly. Then review offset bits, frames, and table size together.
Reading the Output
Start with the page size line. Confirm that it matches the selected offset bits. Next, compare virtual pages with physical frames. A large gap means translation needs careful management. Review table bytes and human readable size. High values suggest multi level paging. Finally, check TLB reach. A small reach can cause more misses when a program touches many pages. Save the exported rows when documenting assumptions for lab reports or design reviews during later comparisons too.
Practical Use
Students can use the calculator to check homework answers. Designers can compare page choices before choosing a memory layout. The process size option estimates pages used by one program. The TLB reach value shows how much memory can be mapped by cached translations. These numbers help explain performance, memory waste, and address design.
FAQs
1. What is page size?
Page size is the fixed block size used by virtual memory. It tells how many bytes each page contains. Common sizes include 4 KiB, 8 KiB, 2 MiB, and 1 GiB.
2. How are offset bits related to page size?
Offset bits identify a byte inside a page. For byte addressing, page size equals two raised to the offset bits. For 12 offset bits, the page size is 4096 bytes.
3. What are virtual pages?
Virtual pages are equal-sized pieces of the virtual address space. They are mapped to physical frames by the page table. The count depends on virtual memory size and page size.
4. What are physical frames?
Physical frames are page-sized blocks in physical memory. A virtual page is loaded into one frame when it is present in main memory. Frame count depends on physical memory size.
5. Why does page table entry size matter?
Each virtual page needs a page table entry. Larger entries store more control information but increase table memory. Table size is the number of entries multiplied by entry size.
6. What is TLB reach?
TLB reach is the memory range covered by cached translations. It equals TLB entries multiplied by page size. Higher reach can reduce translation misses for large working sets.
7. Why can large pages waste memory?
Large pages may leave unused space inside the final page of a process or segment. This unused space is internal fragmentation. It grows when allocations do not fill pages well.
8. Can this calculator handle multi-level paging?
Yes. It estimates entries per table page, index bits per level, selected level coverage, and suggested levels. These values help compare single-level and multi-level table designs.