hi,
I want to allocate a non-paged memory pool of size greater than 64Mb using a kernel driver in windows xp. I have used exallocatepool API but it limits me to just 64mb. Also i also used mmallocatememory API and it creates a 256mb buffer but its slower than exallocatepool API buffer. Is there a way to creating a Ramdisk of size greater than 64mb with the same speed as of the buffer created by exallocatepool API???
Any help would be appreciated. Please i need your help.
Thanks.
Ironhide.
What MmAllocate call are you using, and what are the parameters? It
should not matter which way you allocate the memory unless you mess up
the parameters. Note the slowdown could be because you are taking a
large portion of the available system memory. Why people keep building
ramdisks is beyond me.
Don Burn (MVP, Windows DKD)
Windows Filesystem and Driver Consulting
Website: http://www.windrvr.com
Blog: http://msmvps.com/blogs/WinDrvr
“xxxxx@yahoo.com” wrote in message
news:xxxxx@ntdev:
> hi,
> I want to allocate a non-paged memory pool of size greater than 64Mb using a kernel driver in windows xp. I have used exallocatepool API but it limits me to just 64mb. Also i also used mmallocatememory API and it creates a 256mb buffer but its slower than exallocatepool API buffer. Is there a way to creating a Ramdisk of size greater than 64mb with the same speed as of the buffer created by exallocatepool API???
> Any help would be appreciated. Please i need your help.
>
>
> Thanks.
> Ironhide.
From what I hear about RAMdisks, they are largely an artifact of old MS-DOS
programmers who, without any evidence, assume that they will somehow improve
peformance. Since twenty years ago, RAMdisks were important (in fact, they
were, back then; I had one project that I could change from a 5-hour run to
a 10-minute run with a RAMdisk; today, without the RAMdisk, under Windows
XP, the same program still runs, and takes about 40 seconds, and is every
bit as disk-intensive as it has always been). I think there is this
delusional system that says “RAMdisks are important today because once, long
ago, when we had blindingly fast 20MHz machines and really slow 100ms hard
drives with no caching in the file system, they were important, and nothing
has changed, so they must still be important”.
Sad, really.
joe
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Don Burn
Sent: Saturday, November 20, 2010 9:23 AM
To: Windows System Software Devs Interest List
Subject: Re:[ntdev] Memroy allocation problem
What MmAllocate call are you using, and what are the parameters? It should
not matter which way you allocate the memory unless you mess up
the parameters. Note the slowdown could be because you are taking a
large portion of the available system memory. Why people keep building
ramdisks is beyond me.
Don Burn (MVP, Windows DKD)
Windows Filesystem and Driver Consulting
Website: http://www.windrvr.com
Blog: http://msmvps.com/blogs/WinDrvr
“xxxxx@yahoo.com” wrote in message
news:xxxxx@ntdev:
> hi,
> I want to allocate a non-paged memory pool of size greater than 64Mb
using a kernel driver in windows xp. I have used exallocatepool API but it
limits me to just 64mb. Also i also used mmallocatememory API and it creates
a 256mb buffer but its slower than exallocatepool API buffer. Is there a way
to creating a Ramdisk of size greater than 64mb with the same speed as of
the buffer created by exallocatepool API???
> Any help would be appreciated. Please i need your help.
>
>
>
Thanks.
>
Ironhide.
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