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Monthly Archives: May 2013

dd_rhelp (script for dd_rescue)

Taking forever for ddrescue (or dd_rescue) to run?  Well, why not focus on the good parts of the hard drive first and then worry about the bad sectors afterwards?

dd_rhelp does just this.

More information can be found here:

dd_rhelp is a bash script that handles a very usefull program written
in C by Kurt Garloff which is called dd_rescue, it roughly act as the
dd linux command with the characteristic to NOT stop when it falls on
read/write errors.

This makes dd_rescue the best tool for recovering hard drive having
bad sectors.

Here is a working  example of the program

ddrescue vs dd_rescue

Some great web pages on the differences between ddrescue and dd_rescue

SpinRite Tech Notes

A great overview on how SpinRite works.

(Download the PDF)

SpinRite

This is one of the best and safest tools you can run before a hard drive recovery.

Defcon Talk on HDD Repair

HDD Scan

Need a simple and easy way to test hard drives in a Windows GUI system? Check out HDD Scan.

From the website:

HDDScan is a freeware utility for hard drive diagnostics (RAID arrays, Flash USB and SSD drives are also supported). The program can test storage device for errors (Bad-blocks and bad sectors), show S.M.A.R.T. attributes and change some HDD parameters such as AAM, APM, etc.

HDDScan can be useful for performing the regular “health test” for your drive and predicting its degradation, so you will be able to prevent data loss and backup your files before you will have to contact the data recovery service.

Additionally, software can be used as the hard disk temperature monitor and reading/writing benchmark – performance graph is displayed for every test

SMART Tools

Two great resources for understanding how SMART tools work for hard drives

USB support for SMART tools is flaky, but with this guide, you can see what  is supported.

Scumbag Data Recovery Guy

scumbagITguy

Apple Boot Key Combinations

  • C : Forces most Macs to boot from the CD-Rom drive instead of the internal hard drive. Only works with Apple ROM drives and with bootable CD discs.
  • D : Forces the first internal hard drive to be the startup disk.
  • N : Netboot (New World ROM machines only) – Looks for BOOTP or TFTP Server on the network to boot from.
  • R : Forces PowerBooks to reset their screen to default size (helpful if you’ve been hooked up to an external montior or projector!)
  • T : Target Disk Mode (FireWire) – Puts machines with built-in FireWire into target Disk mode so a system attached with a FireWire cable will have that device show up as a hard drive on their system. Very useful for PowerBooks!
  • Mouse Button Held Down : Ejects any mounted removable media.
  • Shift : Disables all extensions (Mac OS 7-9), or disables Login items when using Mac OS X 10.1.3 or later. Also works when booting Classic mode up just like you were using the OS natively.
  • Option : When using an Open Firmware “New World ROM” capable system, the System Picker will appear and query all mounted devices for bootable systems, returning a list of drives & what OS they have on them. On “Old World” systems the machine will simply boot into it’s default OS without any Finder windows open.
  • Space bar : Brings up Apple’s Extension Manager (or Casady & Greene’s Conflict Catcher, if installed) up at startup to allow you to modify your extension set.
  • Command-V : Boots Mac OS X into “Verbose Mode”, reporting every console message generated during startup. Really shows what’s going on behind the scenes with your machine on startup!
  • Command-S : Boots Mac OS X into “Single User Mode” – helpful to fix problems with Mac OS X, if necessary.
  • Command-Option : Rebuilds the Desktop (Mac OS 7-9).
  • Command-Option-P-R : Erases PRAM if held down immediately after startup tone. Your machine will chime when it’s erased the PRAM, most people will hold this combination for a total of 3 chimes to really flush the PRAM out.
  • Command-Option-N-V : Erases NVRAM (Non-Volatile RAM). Used with later Power Macintosh systems mostly.
  • Command-Option-O-F : Boots the machine into Open Firmware (New World ROM systems only).
  • Command-Option-Shift-Delete : Forces your Mac to startup from its internal CD-ROM drive or an external hard drive. Very helpful if you have a 3rd party CD-ROM drive that is not an Apple ROM device.
  • Command-Option-Shift-Delete-#(where #= a SCSI DEVICE ID) : Boot from a specific SCSI device, if you have your 3rd party CD-ROM drive set to SCSI ID 3, you would press “3” as the # in the combination.

On older computers

  • Command-Option-I : Forces the Mac to read the disc as an ISO-9000 formatted disk
  • Command : Boots with Virtual Memory turned off.
  • Command-Option-T-V : Forces Quadra AV machines to use TV as a monitor.
  • Command-Option-X-O : Forces the Mac Classic to boot from ROM.
  • Command-Option-A-V : Forces an AV monitor to be recognized correctly.

Success Kid

kid