Recovering images from a Compact Flash card

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

My Nikon D70 uses Compact Flash (CF) storage – not the smallest form factor but certainly one of the more established types (and when I bought the camera it was important for my camera to also support IBM/Hitachi microdrives, although with the increasing availability of large-capacity flash cards that’s no longer an issue). I use Lexar Professional cards – usually a 2GB 133x speed card with write acceleration – but this week I’ve had some problems.

In the middle of taking photos of my children, struggling to get them to sit still with my grandparents and for everyone to look towards me (I hate taking portraits), my camera reported an error before it decided that the card was not formatted. I turned the camera off and on again, then shot off a few frames, before the battery indicator told me that I needed to recharge (maybe that was the issue all along). I switched to my spare battery and then continued taking photos with no issues.

When I tried to read the card on my Mac, everything seemed fine (pictures were all there), except that when I ejected it (by right clicking and selecting eject, waiting for the icon to disappear and then waiting a few more seconds) OS X told me that I had removed a device incorrectly and there could be some damage to files. That would be fine if I had just removed the card, but as I had ejected the card properly and the icon had disappeared, it was logical to think that it was safe to remove (Windows may have many faults but at least it confirms when it’s safe to remove a device).

This afternoon, I wanted to copy files from the card before wiping it for a new shoot. Strangely, instead of all my files being neatly numbered DSC_xxxx.JPG, I had DWC_xxxx.JPG and DSC[xxxx.JPG files. They all seemed to preview with no issues in-camera, but some of the files failed to copy to the Mac. I tried again on a Windows Vista PC but with similar issues (at least Windows let me skip the offending files and continue the copy) then, after removing the card and looking again in-camera, I switched back to the Windows machine, where Vista told me that the media appeared to have some damage – did I want to scan and fix it. Thinking that might help me, I let Windows do it’s stuff and, after a very brief interval, it told me that it had succeeded; however all I could see was one 32KB file where the folder used to be with over 700 images in it!

After a mild panic (I had most of those images backed up but there were 16 still to recover), I remembered the Lexar Image Rescue 2 software that came pre-loaded on the CF card when I bought it. I loaded that up on a Windows XP machine (in case there were compatibility issues with Vista) and successfully recovered 747 files from a low level search (which took about an hour for my 2GB card). The 747 resulting .THM files appeared to be JPEGs – at least renaming them *.JPG seemed to work. Then I tried a high-level search – this time I got a number of .CHK files including 712 which corresponded to JPEGs – the difference would appear to be the number of files present in the directory compared with files on disk marked for deletion but not yet overwritten.

Crucially, the recovered files still have the EXIF data letting me work out when they were taken (and therefore helping to narrow down the search for my missing pictures). Once renamed to *.JPG, I could also preview the images with the exception of one files which appear to have been irretrievably corrupted, either by my camera losing power during a write, or by my Mac failing to eject the card properly.

A call for open standards in digital rights management

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

Digital rights management (DRM) is a big issue right now. Content creators have a natural desire to protect their intellectual property and consumers want easy access to music, video, and other online content.

The most popular portable media player is the Apple iPod, by far the most successful digital music device to date. Although an iPod can play ordinary MP3 files, its success is closely linked to iTunes’ ease of use. iTunes is a closed system built around an online store with (mostly) DRM-protected tracks using a system called FairPlay that is only compatible with the iTunes player or with an iPod.

Another option is to use a device that carries the PlaysForSure logo. These devices use a different DRM scheme – Windows Media – this time backed by Microsoft and its partners. Somewhat bizarrely, Microsoft has also launched its own Zune player using another version of Windows Media DRM – one that’s incompatible with PlaysForSure.

There is a third way to access digital media – users can download or otherwise obtain DRM-free tracks and play them on any player that supports their chosen file format. To many, that sounds chaotic. Letting people download content without the protection of DRM! Surely piracy will rule and the copyright holders will lose revenue.

But will they? Home taping has been commonplace for years but there was always a quality issue. Once the development of digital music technologies allowed perfect copies to be made at home the record companies hid behind non-standard copy prevention schemes (culminating in the Sony rootkit fiasco) and DRM-protected online music. Now video content creators are following suit, with the BBC and Channel 4 both releasing DRM-protected content that will only play on some Windows PCs. At least the BBC does eventually plan to release a system that is compatible with Windows Vista and Macintosh computers but for now, the iPlayer and 4 on Demand are for Windows XP users only.

It needn’t be this way as incompatible DRM schemes restrict consumer choice and are totally unnecessary. Independent artists have already proved the model can work by releasing tracks without DRM. And after the Apple CEO, Steve Jobs, published his Thoughts on Music article in February 2006, EMI made its catalogue available, DRM-free, via iTunes, for a 25% premium.

I suspect that the rest of the major record companies are waiting to see what happens to EMI’s sales and whether there is a rise in piracy of EMI tracks; which in my opinion is unlikely. The record companies want to see a return to the 1990s boom in CD sales but that was an artificial phenomenon as music lovers re-purchased their favourite analogue (LP) records in a digital (Compact Disc) format. The way to increase music sales now is to remove the barriers online content purchase.

  • The first of these is cost. Most people seem happy to pay under a pound for a track but expect album prices to be lower (matching the CDs that can be bought in supermarkets and elsewhere for around £9). Interestingly though, there is anecdotal evidence that if the price of a download was reduced and set at around $0.25 (instead of the current $0.99), then people would actually download more songs and the record companies would make more money.
  • Another barrier to sales is ease of use and portability. If I buy a CD (still the benchmark for music sales today), then I only buy it once regardless of the brand of player that I use. Similarly, if I buy digital music or video from one store why should I have to buy it again if I change to another system?

One of the reasons that iTunes is so popular is that it’s very easy to use – the purchase process is streamlined and the synchronisation is seamless. It also locks consumers into one platform and restricts choice. Microsoft’s DRM schemes do the same. And obtaining pirated content on the Internet requires a level of technical knowledge not possessed by many.

If an open standard for DRM could be created, compatible with both FairPlay and Windows Media (PlaysForSure and Zune), it would allow content owners to retain control over their intellectual property without restricting consumer choice.

[This post originally appeared on the Seriosoft blog, under the pseudonym Mark James.]

Some free Windows tools

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

I was recently alerted to the presence of Joe Richards’ PSOMgr tool for managing Windows Server 2008 fine grained password policies and it turns out that Joe has a whole heap of useful tools available for free on his website.

Fine grained password policies for Windows Server 2008 Active Directory Domain Services

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

Another new feature in Windows Server 2008 Active Directory Domain Services is that (at long last) it’s now possible to apply multiple password policies within a single domain using a new feature called fine grained password policies. Now PINs can be used for mobile device access and complex passwords for conventional form factor devices without requiring separate domains, third party software or writing a custom password filter DLL.

The fine grained password policies are user and group based (i.e. not per-OU – in order to avoid extra domain load during login) and multiple policies can be applied; however, the new functionality involves a complex administrative process and there is no GUI yet (although the password settings container can be found if Advanced Features are enabled in Active Directory Users and Computers). Fortunately, Joe Richards has written PSOMgr (a command line tool to manage fine grain password policy password settings objects) and Christoffer Andersson has a similar tool with MMC/PowerShell interfaces.

Improvements in Windows Server 2008 DNS

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

Windows administrators have been waiting to see the back of WINS for years but many applications still rely on single name lables (and multiple DNS name suffixes can become unwieldy). Windows Server 2008 DNS will provide an alternative through its GlobalNames zone (one of several improvements in Windows Server 2008 DNS).

Although it’s not listed in the article linked above, I understand (from Scotty McLeod) that Windows Server 2008 DNS allows the application of a conditional forward (globally – i.e. to all DNS servers) at the domain level; unfortunately, forwarder information still has to be defined on a server-by-server basis.

Musing about panoramic image formats

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

A few years back, I heard UK-based photographer, Nick Meers speak in general terms about landscape photography saying that in order to capture that special image you need to be passionate – and you can’t come back tomorrow! If you don’t make that image now, then you don’t have the passion… even if you do want to get to supper and don’t want to get the tripod out again!

Unfortunately, I find it hard to reconcile that passion with the demands of a young family, so my photography takes a back seat these days and it seems to me that much of the images I create are distinctly mediocre. Some of that mediocrity can be enhanced post-capture but that’s a time consuming process – and anyway, it’s much better to get it right first time.

But is digital editing is really that bad? After all, with traditional (non-digital) methods, photographers have always used filters and darkroom techniques to enhance their images.

Even the viewfinder acts as a censor, selecting just the part of the overall scene that the photographer wants to appear in the final image. The trouble is that I find that the 3:2 aspect ratio used for 35mm film and by many digital cameras often doesn’t seem “right”. Some photographers (e.g. Charlie Waite) specialise in square images whilst others go for a letterbox format – something that I’ve always been attracted to – largely under the influence of one of my favourite photographers, Australia’s Peter Lik. It’s a pleasing format for the eye because it’s how people see. Consequently it is often used for wide-angle landscapes (and so works well in places with a wide field of view) but it not exclusively a wide angle format and can work well for compressed images with a telephoto lens.

Lik (alond with other notable landscape photographers like David Noton uses expensive 6×17 panoramic format cameras with swing lenses but until recently there was an (almost) affordable way to take panoramic images using multiple frames on standard 35mm film – Hassleblad’s X System. Unfortunately Hassleblad withdrew their excellent XPan II camera from sale last year. I’d wanted one for a while but could never justify the expense (at least not once I purchased a digital camera).

In the end, it was digital photography that killed off the XPan – I’d love for Hassleblad to make a digital XPan but the reality is that image sensors come in a particular size and there would be technical hurdles to overcome that would make the product too expensive. Anyway, single images can be stiched together post-capture and now that the quality of digital image sensors has caught up with (and even surpased) film, it’s hard to deride the convenience and low cost of digital photography.

I’m torn – should I save up for a second-hand XPan, buy a digital body with a higher-quality image sensor (so I can crop a decent quality panoramic photo from a single frame), or take separate images and stitch them together?

Windows Server 2008 read only domain controllers

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

This is the last post I’m intending to write based on the content from the recent Windows Server UK User Group meeting – this time inspired by Scotty Mc Leod‘s presentation on read only domain controllers (RODCs), a new feature in Windows Server 2008.

In my post from a few weeks back about some of the new features in Windows Server 2008, I wrote:

Backup domain controllers (BDCs) are back! Except that now they are called read-only domain controllers (with unidirectional replication to offer credential caching and whilst increasing the physical security of remote domain controllers, e.g. in branch offices).

That statement was slightly tongue-in-cheek and, if taken literally would be inaccurate. RODCs are more complex than Windows NT BDCs were. Active Directory still uses a multiple master replication model, but RODCs are really a means of providing a read-only replica of the directory (with outbound replication disabled) – for example at remote sites where to have a fully-functional domain controller would be a security risk. As far as Active Directory is concerned, an RODC is not a domain controller – it actually has a standard workstation account (with some extra attributes).

This has a major advantage in that, unlike a domain controller, an RODC has a local account database, with a local Administrators group (of which Domain Admins will be a member). In effect, this means that a user can be made a full administrator of the RODC, without needing to be a Domain Admin.

In order to create an RODC, the forest and domain need to be at Windows Server 2003 forest functional level with at least one (preferably more) Windows Server 2008 DC present. The forest and domain must also have been prepared for RODCs with adprep /rodc.

The next stage is to provision the computer account, selecting a site, and whether or not DNS/Global Catalog services will be enabled). Control over the information stored on an RODC is controlled with password replications policies – allow/deny lists for replication of passwords based on users, groups or computers. 2 new groups are created – DeniedRODCPassword and AllowsRODCPassword and as for other Windows NT ACLs, deny takes precendence over allow. Next, it’s necessary to define who will manage the RODC – this effectively defines a user account that can administer the server without needing Domain Admins membership (e.g. to apply patches, restart the server, etc.). One gotcha is that this is a user contact (not a group) – many organisations will circumvent this with service accounts, but that’s really not good practice.

Following this, a new computer account should be visible in the directory. The Windows Server 2003 version of Active Directory Users and Computers (ADUC) will see the account as disabled, whereas the Windows Server 2008 tools will report it as an unoccupied DC account. On joining the domain, the computer will be linked with its account and will become an RODC.

The RODC concept relies on a principle called constrained Kerberos delegation, which in turn needs value linked replication – hence the requirement for a Windows Server 2003 domain and forest dunctional level. In addition the requirement for a Windows Server 2008 DC with which to communicate is created as Windows Server 2003 DC will see the RODC as a “normal” computer – e.g. a workstation. Of course, the Windows Server 2008 DC is potentially a single point of failure, so more than one should be deployed.

The constrained Kerberos authentication works as follows:

  • In addition to the krbtgt account that will already exist in the domain (a Kerberos ticket granting service account), each RODC will have its own TGT account created in the form krbtgt_identifier in order to issue its own Kerberos tickets without compromising domain security.
  • If a user attempts to logon at a remote site, their credential
    s will initially be validated by the local RODC.
  • Because password hashes are stripped from RODC replication, if this is the user’s first login attempt, or if they are not in the AllowsRODCPassword group, then the authentication request will be passed across the WAN to a full DC. When the ticket is returned, the RODC asks a full DC running Windows Server 2008 DC replicate a single attribute (the password hash), which is then held for future logins.
  • If a login is authenticated by the RODC then a local Kerberos ticket is issued. This local ticket will not be valid elsewhere on the domain (effectively each RODC becomes a subdomain for authentication purposes) and requests to access other resources will be referred to a full DC running Windows Server 2008.

It is possible to force inbound replication to an RODC for a defined set of users (i.e. to pre-populate the information for users on a particular site); however this information can quickly become stale.

Scotty went on to mention a couple of things to beware of when planning to use RODCs:

  • Because an RODC cannot be written to, some applications will see RODCs as an LDAP server, if an LDAP v3 referral is invoked then many applications will fail.
  • Whilst Exchange Server will treat an RODC as a GC, Outlook will not.

Windows 7

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

With the Windows Vista launch now history and the Windows Server 2008 launch date set for 27 February 2008 (expect to see the first service pack for Vista, codenamed Fiji, around about the same time), speculation has started about the next version of Windows codenamed Windows 7, formerly codenamed both Blackcomb and Vienna.

Of course, at this stage, Microsoft is keeping quiet about what’s in, and what’s out of Windows 7 (very wise) but a good place to watch is Paul Thurrott’s Windows 7 FAQ.

Trying to work out why BlackBerries are so popular (I still don’t get it)

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

Whilst the United States is going iPhone crazy, over on this side of the pond we can’t get one yet… so life goes on.

BlackBerry 7100vA couple of weeks back, I was given a BlackBerry to use at work (until I can get my hands on a Windows-powered phone – one of my colleagues had a greater need than I for the Palm Treo 750v we snagged but there are some new models coming soon on Vodafone
that I can’t talk about but which look pretty cool).

So, if I want a Windows Mobile device (for work) why am I even looking at the BlackBerry? Firstly, I was given it to try (my Nokia 6021 is a bit beaten up these days) and secondly, I’m intrigued as to why these things are held in almost universal acclaim by senior executives, causing chaos in IT departments up and down the country who don’t want to support a (proprietary) messaging platform in addition to their corporate e-mail on Microsoft Exchange or Lotus Domino (and even leading to the nicknaming of London’s Jubilee line between the West End and Canary Wharf as the Blackberry line).

I’ve re-written this post a few times over the last couple of weeks because as I’ve used it, I’ve warmed to the BlackBerry:

  • At first I hated the interface (what is it about mobile phones that, almost without exception, they have such appalling user interfaces?) but that was improved by a software upgrade.
  • I didn’t like that I had to buy a USB 2.0 A to mini 5pin cable to charge the device – and battery life is poor – I get about day’s worth of (light) use for voice only (I know that smartphones are battery-hungry but I don’t have a data plan to use it properly… all I do was make and receive calls). As it happens, the fact that I can use a standard cable to charge the device via USB is pretty useful.
  • I’ve discovered features like the auto on/off capabilities which could have a real use for me (I have a personal phone which friends and family can use to contact me 24×7 – and even though one of my friends recent described me as having workaholic tendencies the work phone is not normally answered in the evening or at weekends).
  • Once you get used the the scroll-click wheel and the button next to it, the user interface becomes a lot easier to navigate – and the 240×260 screen is excellent for viewing photos, although there is no card slot for additional memory (and getting pictures onto the device without a data plan is cumbersome). It looks quite good and feels comfortable in my hand (size and weight). Unfortunately though, I found the keyboard difficult to use – a pretty major failing on a device like this (I think the problem is that it has a qwerty layout but it feels like a mobile phone, so my fingers and thumbs want it to be arranged alphabetically).

I’m not trying to write a product review (for that, refer to Lord Percy or The Register and anyway this particular device is a bit old now so I’m not sure how useful any review that I wrote would be)… this is more of a “this is what I found when I tried to use it” post – I’m hoping that my experience may be useful for others too:

  • After inserting my SIM card, all of my calls went to voicemail – it seems that before you can use the device as a phone you have to turn the wireless on. Not realising that this model doesn’t have WiFi capabilities I thought that “wireless” was referring to IEEE802.11b/g but no – the wireless in question is the GSM radio that is required in order to connect to a mobile carrier.
  • Not having any manuals, etc., I had to find out what the device was first so that I could Google for some help. IMEI number analysis didn’t help (probably because this was originally an evaluation unit), but I eventually discovered that there is an option/setting labelled about, which tells me I have a Blackberry 7100 Wireless Handheld and a bit more searching confirms that its the Blackberry 7100v.
  • I noticed that I still had the previous user’s contacts loaded, so I wanted to wipe the phone – there doesn’t appear to be a delete all option for contacts, so the resolution I used (found on BlackBerry Forums) was:
    • Install Blackberry Desktop Manager (4.2), followed by the BlackBerry Handheld Software v4.1.0.314 for Vodafone (UK) – both of these were downloaded from RIM after searching Google. Following the software update, the device had a totally different (much improved) look and feel. The installation also worked on Windows Vista, despite not being listed as compatible (I ran the installer as an Administrator)
    • Open the BlackBerry Desktop Manager application and create a connection to the device (Connection Settings… from the Options menu).
    • To delete the old data from within Desktop Manager, select Backup and Restore and click the Advanced… button. Select the appropriate device databases (multiples can be selected by Control or Shift clicking) then click Clear.
  • I don’t have a connection to a BlackBerry e-mail service – effectively I’m using the device as a PDA and a phone, but it ought to be possible to set up the BlackBerry as a GPRS modem (not by Bluetooth, but using a USB connection). Unfortunately that’s not working (it should – using the same SIM in my Nokia 6021 allows me to browse the web using GPRS) but I’m unlikely to get anywhere with Vodafone unless I sign up for a BlackBerry service. My BlackBerry alternates between GSM and gprs (depending on signal strength/cell coverage) but never shows GPRS because:
    • GSM – GRPS is not enabled (contact your mobile carrier to sign up to a GPRS plan.
    • gprs (in lower case) – GRPS is enabled, but not been set up for use with a BlackBerry device.
    • GPRS (in upper case) – both GRPS and BlackBerry are enabled, (the service should be enabled for BlackBerry Enterprise Server if Exchange Server connectivity is required, rather than BlackBerry Internet Server).

Even though I’ve warmed to the BlackBerry (and newer models like the curve and the pearl are attractive), I’m still not a convert. Exchange Server 2003 SP2 offers push e-mail too (as does Exchange Server 2007), without requiring another layer of complexity in the organisational IT infrastructure. The dependency on a data plan for even basic things like transferring pictures to/from the device is also a hassle. The jury’s still out on my choice of handset for a personal phone (an iPhone would be nice… but do I really need something that expensive… or on a carrier other than Vodafone? It would be nice to have a decent camera in the device I choose… like the one in the Nokia N95… but last time I had a Symbian smartphone I didn’t get on with the interface. Then again, there are devices like the HTC touch… arghhh, brain overload… too much choice) – in any case, if I have any influence over the selection of my next handset for business it will be running Windows Mobile 6.

Access all of your applications from the OS X Dock

Posted on By Mark Wilson
This content is 18 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

I’m not sure where I picked this tip up but I heard about dragging the Applications folder to the OS X dock in order to provide one-click access to all applications (not just the frequently used ones).

Launching applications from the dock in OS X

At first I was pretty underwhelmed (it didn’t seem to do much except launch a new Finder window) but then I realised that if I click and hold the applications folder icon in my dock then a menu opens up with all the available applications. Dare I say that it’s a bit like a Start Menu for the Mac!