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Performance

A benchmark is used to measure the speed of the software on available targets. This benchmark is in no way complete, but it gives an approximation of the length of time required for common operations on various targets.

Configuration and performance table

All values are in KBytes/sec.

System Medium W0 W1 R
ARM 7 (50 MHz) Hard drive 660 660 680
ARM 7 (50 MHz) Compact Flash, 64MB, Toshiba, IDE mode 1452 1452 1387
ARM 7 (50 MHz) Compact Flash, 64MB, Toshiba, mem-mapped 2368 2368 2206
ARM 7 (50 MHz) MMC / SD using SPI with 12MHz 695 711 1015
ARM 7 (50 MHz) SMC 26 26 495
ARM 7 (33 MHz) NOR flash 23 22 941
ARM 7 (50 MHz) RAM disk 4000 4000 4571

Description of the performance tests

The performance tests are executed as described and in the order below.

W0: Writing

Writing data to a freshly formatted medium in chunks of 64kBytes, using 80% of the capacity of the medium but no more than 3.2MByte.

W1: Writing

Writing data to a medium in chunks of 64kBytes, using 80% of the capacity of the medium but no more than 3.2MByte.

R: Reading

Reading data from a freshly formatted medium in chunks of 64kBytes. using 80% of the capacity of the medium but no more than 3.2MByte.

CLICK HERE for Ordering Information. 

Memory footprint

The file system is designed to fit many kinds of embedded design requirements. Several features can be excluded from build to get a minimal system that can efficiently access any FAT media.

In the following section memory usage for different typical 16 and 32- bit systems is listed.
Please note that the values are valid for the given approximate values. Features can affect the size of others. For example if FAT32 is deactivated, the format function gets smaller because the 32 bit specific part of format is not added into the compilation.

This minimal configuration supports FAT12/16, but has no media format features, no directory support, no free disk space function (DiskInfo) and only one file can be opened at a time:

The configuration file (FS_Conf.h) looks as follows:

#define FS_POSIX_DIR_SUPPORT 0
#define FS_FAT_NOFORMAT 1
#define FS_FAT_DISKINFO 0
#define FS_FAT_NOFAT32 1
#define FS_MAXOPEN 1

16-bit CPUs

System

Detail Description
CPU M16C
Tool chain IAR Workbench for M16C V2.12A
Memory Model Data model: Near pointer; Constants: near memory
Compiler options Highest size optimization
Device driver MMC/SD driver

Memory requirements

Detail ROM [Bytes] RAM [Bytes]
Minimal file system 11384 1122
MMC/SD driver +2172 528
Additional support for
Directory +2654 +1310 (for each directory)
(Auto) format +2175 0
Diskinfo +758 0
FAT32 +658 0
 
Additional open files 0 1060

32-bit CPUs

System

Detail Description
CPU ARM 7
Tool chain IAR Workbench for ARM V4.11A
Memory Model ARM7, thumb instructions; no interwork;
Compiler options Highest size optimization;
Device driver MMC/SD driver

Memory requirements

Detail ROM [Bytes] RAM [Bytes]
Minimal file system 10298 1129
MMC/SD driver +2358 532
Additional support for
Directory +2208 +1328 (for each directory)
(Auto) format +2056 0
Diskinfo 488 0
FAT32 352 0
 
Additional open files 0 1068
 
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