Which is quicker - ...
 
Notifications
Clear all

Which is quicker - Linux DD or Hardware

10 Posts
6 Users
0 Reactions
937 Views
(@markl1975)
Trusted Member
Joined: 16 years ago
Posts: 63
Topic starter  

Hello,

I thought I'd ask the question here as there may be someone who can give me some more insight into this.

I have a colleague in the Forensic industry who swears by dd.exe. When imaging discs he uses a Shuttle PC with a Linux distro on it to dd a hard drive to an external caddy, connected straight to the SATA controller on the motherboard. It's quite bulky, but he swears it's faster than using hardware.

I personally use Tableau kit. I have a TD1 with the various write-blockers to image drives and media. I've always found them quick, and more importantly, portable.

Does anyone else use a similar setup to the above PC? If so, is it faster than using hardware, and what setup/Linux distro do you use?

Many thanks,

Mark


   
Quote
(@twjolson)
Honorable Member
Joined: 17 years ago
Posts: 417
 

I haven't tested this, but I'd say that any differences would be minimal. The slowest link in the data transfer chain isn't going to be the interface, but the hard drive itself. It takes time for the heads to seek and find. If I am correct, then both methods should be roughly equivalent. This of course assumes that all other factors are equal other than the interfaces.

You two could have a race, winner buys the buffalo wings.


   
ReplyQuote
mstew
(@mstew)
Active Member
Joined: 18 years ago
Posts: 6
 

These are some results from TD-1 (with hashing) that i used the other day without the new firmware update. I don't know if you can beat these speeds with dd. but then again that all depends on your system/hardware setup.

Created 2010-05-20 1012
Closed 2010-05-20 1119
# of sectors 625,142,448 (320.0 GB)
Errors recorded 0

Created 2010-05-20 1209
Closed 2010-05-20 1341
# of sectors 625,142,448 (320.0 GB)
Errors recorded 0


   
ReplyQuote
(@Anonymous 6593)
Guest
Joined: 17 years ago
Posts: 1158
 

It's quite bulky, but he swears it's faster than using hardware.

Well, dd is not exactly non-configurable – a suitable choice of bs=??? probably helps a great deal. And just possibly what the driver does with a multi-sector request – does it do a read for all sectors in one go, or does it do sector-by-sector read.

There are too many parameters involved for this to be a simple question to answer.


   
ReplyQuote
(@patrick4n6)
Honorable Member
Joined: 16 years ago
Posts: 650
 

Using mstew's fastest time there, that's an average data transfer rate of 4.78 GB/min or 79 MB/sec. I've had transfer rate averages over 90MB/s with the latest generation of desktop drives (Seagate 7200.12) as the source and destination in my testing of dd with MD5 hashing inline.

I have a very similar configuration to what the OP describes - a Shuttle SFF PC with a forensic linux build - as part of my field kit. It's option 3 now of my 3 standard field acquisition methods.

Frankly though, I'm finding that some solutions that run under Windows 7 are almost as fast, especially in the lab where I'm imaging to a RAID.


   
ReplyQuote
(@markl1975)
Trusted Member
Joined: 16 years ago
Posts: 63
Topic starter  

Patrick4n6,

I'd like to build a couple of these configurations in our lab, just to test.

Would you be able to PM your PC builds, and which Linux Forensic distro you use?

The only software we run under Windows 7 is Tableaus TIM v1.1. Do you image to an externally attached RAID, or are you imaging using a PC with a RAID controller on board?

Many thanks for your help,

Mark


   
ReplyQuote
Fab4
 Fab4
(@fab4)
Estimable Member
Joined: 18 years ago
Posts: 173
 

It's option 3 now of my 3 standard field acquisition methods.

With no desire to hijack the thread and just out of interest, what are your other 2 options?


   
ReplyQuote
(@patrick4n6)
Honorable Member
Joined: 16 years ago
Posts: 650
 

Patrick4n6,

I'd like to build a couple of these configurations in our lab, just to test.

Would you be able to PM your PC builds, and which Linux Forensic distro you use?

The only software we run under Windows 7 is Tableaus TIM v1.1. Do you image to an externally attached RAID, or are you imaging using a PC with a RAID controller on board?

Many thanks for your help,

Mark

Generally, if I'm going to answer a question, I'm going to do it to the whole board rather than PM. The only exception is certain stuff related to law enforcement.

I have an older P4 shuttle which I'm going to replace at some point. It's an SB65G2 with a P4 3GHz CPU and 2GB DDR400 RAM. I'm using the SPADA forensic linux distro, which is limited to LEO and IACIS members, but I've also tested it with Raptor, which was for some strange reason slower.

When I said "image to RAID" I meant in my lab, to my i7 w/ Adaptec RAID. Also, those speed tests were done on my i7, but the newer Shuttles should get the same result.

To answer Fab4, my other 2 options are forensic boot disk and laptop w/ Tableau T35es & FTK Imager. Once I validate the new TIM with the improved naming, I may change over.


   
ReplyQuote
(@markl1975)
Trusted Member
Joined: 16 years ago
Posts: 63
Topic starter  

Hello,

I downloaded the SPADA-4 iso after searching for it on Google. Is this the same one you use? Our department works alongside the UK Police, so if there is a special version for LEO types, we should be able to download it.

Many thanks,

Mark


   
ReplyQuote
(@patrick4n6)
Honorable Member
Joined: 16 years ago
Posts: 650
 

Looks like PK has opened up distribution outside LEOs now. If you got it from spada-cd.info, then you have the right one.


   
ReplyQuote
Share: