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Windows System Call Tables

The repository contains system call tables collected from all modern and most older releases of Windows, starting with Windows NT.

Both 32-bit and 64-bit builds were analyzed, and the tables were extracted from both the core kernel image (ntoskrnl.exe) and the graphical subsystem (win32k.sys).


The data is formatted in the CSV and JSON formats for programmatic use, and as an HTML table for manual inspection.

The HTML files are also hosted on my blog under the following links:

Operating systems

The following major versions of Windows are included in the tables:

System x86 versions x64 versions
Windows NT SP3 Terminal Server, SP3, SP4, SP5, SP6
Windows 2000 SP0, SP1, SP2, SP3, SP4
Windows XP SP0, SP1, SP2, SP3 SP1, SP2
Windows Server 2003 SP0, SP1, SP2, R2, R2 SP2 SP0, SP2, R2, R2 SP2
Windows Vista SP0, SP1, SP2 SP0, SP1, SP2
Windows Server 2008 SP0, SP2 SP0, SP2, R2, R2 SP1
Windows 7 SP0, SP1 SP0, SP1
Windows Server 2012 SP0, R2
Windows 8 8.0, 8.1 8.0, 8.1
Windows 10 1507, 1511, 1607, 1703, 1709, 1803, 1809, 1903, 1909, 2004, 20H2 1507, 1511, 1607, 1703, 1709, 1803, 1809, 1903, 1909, 2004, 20H2

Windows Server 2016 and later are not included, as their syscall tables are equivalent to that of Windows 10:

Windows Server version Windows 10 release
2016 LTSC (1607) 1607
1709 1709
1803 1803
2019 LTSC (1809) 1809
1903 1903
1909 1909
2004 2004
20H2 20H2

Historical system call counts

Below is a line chart showing the progression of Windows system call development over time. It covers all major desktop versions of Windows starting with Windows NT 4.0 released in August 1996, up to the most recent versions of Windows 10. Server editions are not included as their kernels are equivalent to their desktop counterparts. The analysis was performed on x86 builds for consistency, as this is the only CPU architecture which covers all available systems. There might be very small differences on x64 builds of the kernel or the less popular editions (e.g. Windows NT 4.0 Terminal Server), but they are insignificant for the purpose of this overview chart.

Historical system call counts


We would like to thank the following contributors to the project: Woodmann, Deus, Gynvael Coldwind, MeMek, Alex, Omega Red, Wandering Glitch.


Mateusz 'j00ru' Jurczyk (


Windows System Call Tables (NT/2000/XP/2003/Vista/2008/7/2012/8/10)



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