Data Replay Services

Computer Crime / Digital Discovery / CCTV Image Recovery / Computer Forensics

Archive for October, 2015

How Do You Get Data from an Unresponsive Hard Disk?

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A Seagate HDDIt’s important to break the goal down into achievable, logical steps that flow from one and other. When breaking down goals in steps, it’s critical to get as much useful information as possible about the problem as the more information we have, better and more achievable our goal will be. Say for example that my goal is to retrieve a document file from my unresponsive hard disk – the steps I need to come up with solve the goal. This can be described as follows:

Goal: Retrieve document from unresponsive hard disk
Step to achieve goal:
1. Diagnose problem with disk
2. Work out how to solve the problem
3. Implement the repair
4. Retrieve document

Now let’s break this procedure down even further and supply some more information:

  • Western Digital HDD hard drive
  • Still recognised by the computer
  • Computer unable to access drive’s data area

These three pieces of information provide crucial information to aid our decision making process, but the piece of information you may consider to be the most crucial (that the drive is a Western Digital) is actually the least useful. All hard drive use the same architecture, so Seagate, Western Digital and Toshiba hard drives all use similar components and work on the same principles.

The first piece of useful information is that the hard drive type is an HDD rather than an SSD. This tells us that the architecture of the drive is the old mechanical type rather than that based on solid state (SSD) memory. This means the drive has moving parts and is susceptible to mechanical damage.

Despite this being the case, we are able to rule of the possibility of mechanical failure as the hard drive is still recognised by the computer. This is because HDD type hard drives that have mechanical faults are not recognised by the computer because the hard drive is unable to communicate with the computer to identify itself.

Moreover, by ruling out what the problem isn’t it becomes easier to identify what the problem is. If the problem is not mechanical, the what else could it be? Well, the problem is not electrical either because again, the hard drive is still being recognised. Any electrical device that relies on power will not work if that power source is not working. Therefore we can also rule out the possibility of electrical problems.

It’s at this point that we need to take a close look at the “unresponsive” nature of the fault. If we look at it closer, the hard drive isn’t unresponsive at all, it’s just unresponsive to the computer. So what could the problem be?

The symptoms point to bad sectors – parts of the hard drive that become unresponsive and it’s at this point that a data recovery service is required. I’ve used the company Data Clinic as an example, as they are one of the best and well know companies in the United Kingdom to use to retrieve documents from unresponsive hard drives.

Sometimes you don’t actually need to use the services of a company like Data Clinic, and can repair the hard drive yourself, but situations like this are few – usually the only time you can progress with a ‘DIY’ approach is when there isn’t anything wrong with your hard drive. “Hang on…”, I hear you say, “If there’s nothing wrong with my hard drive why would I need a data recovery service?”. Well, sometimes the cause of the problem is a data or file system error – such as those caused by a virus or an unsuccessful software install – both these situations can be fixed by the “DIY” approach – see this page as a great example of example hard disk problems and issues that are commonly found.

So, armed with the above information you will now hopefully be fully equipped to sort out your unresponsive hard drive, if you are still stuck why not contact me for further advice?

Written by Betty

October 27th, 2015 at 12:39 pm

Thoughts On CCTV

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Most budget CCTV systems comprise of one or more cameras that connect to a Digital Video Recorder box. Housed inside the DVR are one or more hard drives onto which the data is recorded.

The video images are often recorded in a compressed form in order to save storage space on the hard drives. Because CCTV recorders are saving data almost continuously, large amounts of storage space are needed in order to hold all the data.

To keep costs down and save on the amount of storage space required, DVRs can be programmed to hold data for a specific number of days, after which they loop back to the beginning of the recording and start to overwrite data. So, as an example, a DVR system that is set to only hold the last 7 days of data will do just that, and when it gets to day 8, this will be overwriting the data from day 1 etc etc.

The Recovery of CCTV Images

I am often asked if it is possible to recover data from CCTV systems where the hard drive’s data has been overwritten, so for example, is it possible to get data back from days 8 or further in the past? The answer, is usually no, but sometimes yes – it entirely depends how the data has been recorded on the hard drive. Samsung CCTV systems for example, record their data differently to Panasonic CCTV systems, and different approaches are used to rescue the images from both.

Written by Betty

October 16th, 2015 at 3:30 pm

Posted in Computer Crime