The Digital Life, Houston We Have a Problem, 080 25/04/08
I know how hard drives
work, they whizz round and the gramophone needle reads off the data. But memory
sticks with no moving parts? How do they handle files? How can they retain data
even when away from the USB port?
Arnult Handley, by
It’s all clever stuff and
the technology in question is known as ‘non-volatile’ Flash Memory. It crops up
all over the place nowadays, from USB pen drives and digital camera memory
cards to MP3 players and mobile phones.
Data is stored in ‘cells’
by devices called floating gate transistors – well, you did ask… There are
millions of them in a memory chip and each cell stores a single ‘bit‘ of data
in the form of a tiny electrical charge (some newer types of flash memory can
store several bits per cell). To stop the charge leaking away the gate – the
part of the transistor where the charge is stored – is sandwiched or ‘floats’
between two layers of insulating material. Every time the device is used the
charges are refreshed but if it isn’t accessed for some time, 4 or 5 years,
say, the charges may dissipate and data may be lost or corrupted. Otherwise
flash memory devices are usually very rugged and unlike most other data storage
systems are largely immune to vibration and mechanical shock, magnetic fields,
X-Rays and quite wide variations in temperature and humidity
Data on Flash Memory
chips is organised in a similar way to a hard disc drive and stored in the form
of ‘blocks’, made up of 512 or 2048 bytes (a byte is 8 bits). Most flash memory
devices use the long established FAT 32 (File Allocation Table) filing system,
to ensure the broadest compatibility, and as far as PCs old and new are
concerned they appear to be an extra disc drive.
Can you tell me how to use my mouse with just one click
instead of two?
Roy Chitty, by email
This annoys a lot of people because you only need a single
click to navigate web pages and program menus, but two, to open folders and
launch programs from the desktop. A single-click option is available in
Windows, but not where you might expect to find it, in Mouse settings in
Control Panel. In Windows Explorer (Explorer or Computer in Vista) go to Tools
> Folder Options and select the General tab and under ‘Click items as
follows’ select ‘Single-click to open an item’. Click OK or Apply to make it
We watch DVDs on our
laptop whilst overseas and wondered if there's any way to increase the volume
level? We maximise the volume on the task-bar icon or using the function
button on the keyboard, but with some films it is still a struggle to hear
Rebecca Winch, by email
The tiny speakers on
most laptops are designed to be heard at normal screen viewings distances (i.e.
half a metre or so. Some high-end multimedia machines have a little more oomph
in the sound department but in general, if the volume controls are at maximum
that’s as loud as it gets. The simplest way to boost the volume for communal
viewing is to connect the laptop’s earphone socket to the external line input
of a home hi-fi system. If that’s not possible then you could use a set of
amplified PC speakers. A basic outfit will set you back around £20, more
powerful systems, with larger speakers and a sub-woofer, capable of doing
justice to blockbuster DVD soundtracks start at £70 or so. If it’s just you
watching try using ear or headphones.
Home and Away from
We spend quite a lot
of time in California at our daughter’s home. How can we get UK TV over there?
American TV is to say the least unbelievably poor. We have a laptop and we
subscribe to Sky TV.
Ken Davison, Earby
It is possible, maybe… In
an ideal world you would be able to access Internet TV services like BBC iPlayer.
itv.com and 4oD, anywhere in the world but a complex tangle of copyright and
licensing issues means these are only available if you are actually in the UK.
There are ways to get around DRM (Digital Rights Management) restrictions,
using something called a proxy server, but it’s not easy or reliable and the
results are usually poor.
There is a gadget called
Slingbox (www.slingmedia.com/), which
connects between your digital TV tuner and broadband modem/router. Once
installed you can use your laptop to ‘call home’, from anywhere with a
broadband connection, control your TV tuner and stream programs over the
Internet back to your computer.
It can work quite well,
especially if you have cable broadband at home, but the results can be variable
on normal ADSL broadband connections (i.e. broadband through your phone line).
This is because the Slingbox sends data ‘upstream’ through your home modem, and
upload speeds are generally much slower than download speeds. On a slow
broadband connection, and at peak times, the streamed programme can be jerky or
prone to interruptions and picture quality may not be very good, especially if
the display is set to full screen.
© R. Maybury 2008 0704