<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Hi,<br>
<br>
Just a few quick answers to help you get started:<br>
<br>
1)<br>
a) You can specify multiple disks in a .parv file without using
disksim_iomap, and devno would be then used to distinguish between
the different disks.<br>
b) blkno is the sector number. The default size of a sector is 512
bytes.<br>
c) bytecount is the number of bytes. It needs to be divisible by
the sector size (usually 512 bytes).<br>
<br>
I am not sure about 2) or 3), but here is what I think:<br>
<br>
2) To the best of my knowledge, there is not much support for this.
The SSD module simulates the wearing out of flash. I didn't yet find
anything else that would simulate a failure.<br>
<br>
3) I think you should be able to do this...<br>
<br>
I hope this helps.<br>
<br>
Best,<br>
-Peter<br>
<br>
<br>
On 01/05/2012 03:48 PM, Ricardo Rey wrote:
<blockquote
cite="mid:CACpOm-96KfEyxbofBAxHRH56t0cv3Avz0AkB2jyANTRwJgYzKw@mail.gmail.com"
type="cite">Hi, all!<br>
<br>
Thanks to Peter Macko's answer from my previous question I know
where to start to use Disksim as a slave from another code, and I
have already<br>
gone through syssim_driver.c many times, so I think I already have
somewhat of a picture of how it works.<br>
<br>
However, I still have some questions about some situations which
are not considered in syssim_driver.c, or which I at least have
not yet understood:<br>
<br>
1) I don't fully understand the disksim_request structure, so some
of its fields raise some questions:<br>
<br>
a) Device number (devno). Is this used as a reference of which
disk receives the request, in case there is more than one disk? If
so... which device number<br>
makes reference to which disk? In the .parv files in
./valid, the only one that I've found that has more than one disk
instantiated is ascii.parv (18 disks), and the<br>
mapping is done using disksim_iomap {}... but I cannot
match the tracedev and simdev parameters to the device number.<br>
b) Block number: I have no idea what this is. In the example
they use the third input parameter (argv[3]) and a random number
to generate "r.blkno"... but I don't know what<br>
it is used for<br>
c) Request size (bytecount): this is pretty self expanatory.
My issue is this: what is the "unit" of this parameter? Is it in
bytes? In sectors? According to what I've read it must be<br>
in bytes, because there is a line where this value is
divided by 512 (which is the sector size), thus resulting in a
one-sector size... if this value is less than 512, there is an
assert<br>
that fails (bcount > 0 turns out to be false). Can
someone tell me, then, what is the unit of this field?<br>
<br>
2) Part of this project requires the simulation of errors (say, a
disk failure, a bus failure, etc)... does Disksim provide this
kind of simulation? (The probability of failure of a disk given<br>
some information about it, like how old it is, the type and
brand, etc).<br>
<br>
3) My question about the device number brings me to another issue:
if it is possible to send requests to different disks, is it
possible to process each request at the same time?
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Disksim-users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Disksim-users@ece.cmu.edu">Disksim-users@ece.cmu.edu</a>
<a class="moz-txt-link-freetext" href="https://sos.ece.cmu.edu/mailman/listinfo/disksim-users">https://sos.ece.cmu.edu/mailman/listinfo/disksim-users</a>
</pre>
</blockquote>
<br>
</body>
</html>