linux-kernel - Re: Generic Disk Driver in Linux

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <44EE0DDA.5060600@cfl.rr.com>
Date:	Thu, 24 Aug 2006 16:36:42 -0400
From:	Phillip Susi <psusi@....rr.com>
To:	Aleksey Gorelov <dared1st@...oo.com>
CC:	arjan@...radead.org, jengelh@...ux01.gwdg.de,
	daniel.rodrick@...il.com, linux-kernel@...r.kernel.org,
	kernelnewbies@...linux.org, linux-newbie@...t.kernel.org,
	satinder.jeet@...il.com
Subject: Re: Generic Disk Driver in Linux

The int 13 calls to the bios can only accept addresses within the first 
1 MB of memory, and the calls are synchronous, so DMA really doesn't 
matter as the cpu will be busy waiting anyhow while the IO takes place, 
which will wreak all kinds of hell on the rest of the running system, 
including other hardware ISRs.


Aleksey Gorelov wrote:
>> thing will be really really bad... (hint: real mode can access only 1Mb
>> of memory, so you will bounce buffer all IO's)
> This is true for non-dma case only. As I already mentioned before, most BIOSes 
> support dma, and there is no 1Mb limit for that (at least on modern hw).
> 
> Aleks.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/