Understanding Registry Value Data Types

by Barry Dysert
(last updated June 19, 2017)

2

If you ever have to get into the registry, you may be curious to know what value data types exist. Every key's value is assigned a data type. The list of valid data types includes:

  • REG_SZ. A null-terminated string
  • REG_BINARY. Binary data
  • REG_DWORD. A 32-bit number
  • REG_QWORD. A 64-bit number
  • REG_MULTI_SZ. A sequence of null-terminated strings, terminated by a null value
  • REG_EXPAND_SZ. A null-terminated string that contains unexpanded references to environment variables (like %PATH%)

Of course, if you're editing the registry you'll need to use the data type appropriate for the key you're creating. For example, there's a registry tweak you can do that will disable Windows from constantly checking for low disk space (and therefore increase by a bit the amount of resources available for other things). This is at HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies. If you click on the "Explorer" folder you can create a key named "NoLowDiskSpaceChecks". To disable Windows from doing the disk space checking, you want to put a 1 in for that key's value.

Obviously, you could use a data type of REG_BINARY, REG_DWORD, or REG_QWORD since they will all hold the value 1 with no problem. I used REG_DWORD, though, since there may come a time when the key may take on more than two values, so I wouldn't want to be limited to REG_BINARY. And REG_QWORD seems like a lot of space to simply hold a 1.

 This tip (13035) applies to Windows 7, 8, and 10.

Author Bio

Barry Dysert

Barry has been a computer professional for over 30 years, working in different positions such as technical team leader, project manager, and software developer.  He is currently a senior software engineer with an emphasis on developing custom applications under Microsoft Windows. ...

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What is one minus 1?

2017-09-06 04:19:20

Barry

I think the space savings would be negligible, and i wouldn't want to try it anyway. Sounds like that would be asking for trouble.


2017-09-06 01:12:48

Amaroq Starwind

Would Windows function correctly if you changed some of the default DWORD values to regular BINARY values? And would doing so use less space?


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