Difference between revisions of "SEGGER standard for units of Memory size"

From SEGGER Wiki
Jump to: navigation, search
(Created page with "This article describes the units used by SEGGER for sizes and speeds, in manuals and on the web. __TOC__ = Speed units = * Always metric: Powers of 10 * kB/s = 1000 bytes pe...")
 
m
Line 1: Line 1:
  +
In computing, the logical size of a memory is usually a power of two.
  +
The same is true in most Embedded Systems, which is memory sizes such as the size of Flash memory or RAM
  +
are usually given in units of 2^10 = 1024 bytes or 2^20 = 1048576 bytes.
  +
These have historically been call kB and MB.
  +
Unfortunately, this conflicts with the SI-System, where the k-prefix stands for 1000 (10^3) and the M-prefix represents 1000000 (10^6).
  +
  +
  +
  +
 
This article describes the units used by SEGGER for sizes and speeds, in manuals and on the web.
 
This article describes the units used by SEGGER for sizes and speeds, in manuals and on the web.
   
 
__TOC__
 
__TOC__
  +
  +
= Prefixes =
  +
SEGGER has adopted the following convention on prefixes:
  +
* k = 1000 (10^3)
  +
* K = 1024 (2^10)
  +
* M = 1000000 (10^6)
  +
* Mi = 1048576 (2^20)
  +
These are being used in also SEGGER products and documents. However, this is a process that will take some time, and older programs and documents will not be updated.
   
 
= Speed units =
 
= Speed units =

Revision as of 22:42, 1 June 2021

In computing, the logical size of a memory is usually a power of two. The same is true in most Embedded Systems, which is memory sizes such as the size of Flash memory or RAM are usually given in units of 2^10 = 1024 bytes or 2^20 = 1048576 bytes. These have historically been call kB and MB. Unfortunately, this conflicts with the SI-System, where the k-prefix stands for 1000 (10^3) and the M-prefix represents 1000000 (10^6).



This article describes the units used by SEGGER for sizes and speeds, in manuals and on the web.

Prefixes

SEGGER has adopted the following convention on prefixes:

  • k = 1000 (10^3)
  • K = 1024 (2^10)
  • M = 1000000 (10^6)
  • Mi = 1048576 (2^20)

These are being used in also SEGGER products and documents. However, this is a process that will take some time, and older programs and documents will not be updated.

Speed units

  • Always metric: Powers of 10
  • kB/s = 1000 bytes per second
  • MB/s = 1'000'000 bytes per second

Size units

  • Typically binary: Powers of 2
  • Rarely metric: Powers of 10
  • KB = 1024 bytes
  • MiB = 1'048'576 bytes
  • kB = 1000 bytes
  • MB = 1'000'000 bytes