10-15-2004
Quote:
Originally posted by Driver
> Heh. That's something that puzzles me about most textbook algorithms too, dude. But this is definitively possible to reduce I/O
> while adding some CPU overhead; think of the tree/hash used databases...
I'm not ``puzzled'' about the concept of trading processing time versus I/O; I merely asked you to back up your claim that it is actually possible and meaningful to do so, in this particular case.
I pasted link to FreeBSD's fts. It does it.
Quote:
> Most fts should be similar, if not better (especially considering that this one is very old and really free (so it could have been forked a few
> times)).
Most fts ... I thought we had already established that fts is a BSD thing
Most OSes will use something similar for rm/chmod/du/find, etc. I call these things fts. At the very least, their du must be implemented correctly.
Quote:
> Just consider this one a proof of concept if you want...
Proof of WHAT concept? It calls opendir(), readdir() and stat() as well, just like your own implementation would. You have yet to show what it is that's supposed to make this code less I/O intensive and thus faster than a straightforward manual implementation here! And keep in mind that an ad-hoc solution can also save all the bookkeeping work; It can stat() a file and throw it away, without all the ``bloat'' found in fts.c.
fts is bloated, but it is faster and secure. See source code.
Quote:
Anyway. If you don't mind, I will leave this fruitless discussion in favor of something more productive.
Sure.
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hi,
It would be of great help if anyone can tell me what is the command for getting the size of a directory.
Thx a lot in advance
Minaz (9 Replies)
Discussion started by: minazk
9 Replies
2. UNIX for Dummies Questions & Answers
hi, say i have the following directory structure a/b/c/d...
can i do df -kt /a/b/c/d and the output will gives me the total space of the directory space in d? or the output will just be the total space of the parent directory a.
hope its clear.. (2 Replies)
Discussion started by: yls177
2 Replies
3. AIX
hello
When i do a "ls -l" in a directory (Aix 5.3), i have the result :
>ls -l
total 65635864
-rw-r--r-- 1 lobi system 2559909888 Feb 20 15:06 cible5.7bdat
-rw-r--r-- 1 lobi system 1020098870 Feb 20 13:06 cible6.7bdat
-rw-r--r-- 1 lobi system 1544789511 Feb 20 11:06 cible9.7bdat
-rw-r--r--... (2 Replies)
Discussion started by: pascalbout
2 Replies
4. UNIX for Dummies Questions & Answers
am I right in assuming that in unix a directory size is just information about that directory stored somewhere on the file system, and not a sum of its contents? This is because ls -l gives 1024 as my directory size, when the directory contains many gigs worth of stuff.
also, is
du -sk dir ... (2 Replies)
Discussion started by: JamesByars
2 Replies
5. Shell Programming and Scripting
Hello again;
I have a directories and subdirectories in my current directory and i wanna to find the directories( and subdirectories ) which are larger than what user enters as first parameter.
find . -type d -size +"$1"c -print > directories.dat
I used this command and i am not sure it is... (19 Replies)
Discussion started by: redbeard_06
19 Replies
6. Solaris
Hi,
We currently have an Oracle database running and it is creating lots of processes in the /proc directory that are 1000M in size. The size of the /proc directory is now reading 26T. How can this be if the root file system is only 13GB?
I have seen this before we an Oracle temp file... (6 Replies)
Discussion started by: sparcman
6 Replies
7. UNIX for Dummies Questions & Answers
find . -type d -print 2>/dev/null|awk '!/\.$/ {for (i=1;i<NF;i++){d=length($i);if ( d < 5 && i != 1 )d=5;printf("%"d"s","|")}print "---"$NF}' FS='/'
Can someone explain how this works..??
How can i add directory size to be listed in the above command's output..?? (1 Reply)
Discussion started by: vikram3.r
1 Replies
8. Solaris
Hi,
How to get size of particular directory?
Thanks (5 Replies)
Discussion started by: cutefriend
5 Replies
9. Shell Programming and Scripting
To find the whole size of a particular directory i use "du -sk /dirname".. but after finding the direcory's size how do i make conditions like if the size of the dir is more than 1 GB i hav to delete some of the files inside the dir (0 Replies)
Discussion started by: shaal89
0 Replies
10. UNIX for Dummies Questions & Answers
I have been searching both on Unix.com and Google and have not been able to find the answer to my question. I think it is partly because I can't come up with the right search terms.
Recently, my virtual server switched storage devices and I think the problem may be related to that change.... (2 Replies)
Discussion started by: jmgibby
2 Replies
LEARN ABOUT CENTOS
tpm_quote_tools
TPM QUOTE
TOOLS(8) TPM QUOTE TOOLS(8)
NAME
TPM Quote Tools
PROGRAMS
tpm_mkuuid, tpm_mkaik, tpm_loadkey, tpm_unloadkey, tpm_getpcrhash, tpm_updatepcrhash, tpm_getquote, tpm_verifyquote
DESCRIPTION
TPM Quote Tools is a collection of programs that provide support for TPM based attestation using the TPM quote operation.
A TPM contains a set of Platform Configuration Registers (PCRs). In a well configured machine, some of these registers are set to known
values during the boot up process or at other times. For example, a PCR might contain the hash of a boot loader in memory before it is
run.
The TPM quote operation is used to authoritatively verify the contents of a TPM's Platform Configuration Registers (PCRs). During provi-
sioning, a composite hash of a selected set of PCRs is computed. The TPM quote operation produces a composite hash that can be compared
with the one computed while provisioning.
To use the TPM quote operation, keys must be generated. During provisioning, an Attestation Identity Key (AIK) is generated for each TPM,
and the public part of the key is made available to entities that validate quotes.
The TPM quote operation returns signed data and a signature. The data that is signed contains the PCRs selected for the operation, the
composite hash for the selected PCRs, and a nonce provided as input, and used to prevent replay attacks. At provisioning time, the data
that is signed is stored, not just the composite hash. The signature is discarded.
An entity that wishes to evaluate a machine generates a nonce, and sends it along with the set of PCR used to generate the composite PCR
hash at provisioning time. For this use of the TPM quote operation, the signed data is ignored, and the signature returned is used to val-
idate the state of the TPM's PCRs. Given the signature, the evaluating entity replaces the nonce in the signed data generated at provi-
sioning time, and checks to see if the signature is valid for the data. If so, this check ensures the selected PCRs contain values that
match the ones measured during provisioning.
A typical scenario for an enterprise using these tools follows. The tools expect AIKs to be referenced via one enterprise-wide Universally
Unique Identifier (UUID). The program tpm_mkuuid creates one.
For each machine being checked, an AIK is created using tpm_mkaik. The key blob produced is bound to the UUID on its machine using
tpm_loadkey. The public key associated with the AIK is sent to the entities that verify quotes. Finally, the expected PCR composite hash
is obtained using tpm_getpcrhash. When the expected PCR values change, a new hash can be generated with tpm_updatepcrhash.
The program to obtain a quote, and thus measure the current state of the PCRs is tpm_getquote. The program that verifies the quote
describes the same PCR composite hash as was measured initially is tpm_verifyquote.
SEE ALSO
tpm_mkuuid(8), tpm_mkaik(8), tpm_loadkey(8), tpm_unloadkey(8), tpm_getpcrhash(8), tpm_updatepcrhash(8), tpm_getquote(8), tpm_verifyquote(8)
Oct 2010 TPM QUOTE TOOLS(8)