Web Design Whim

Archive for the ‘Tech Spot’ Category

OK, you have a laptop/notebook/netbook.  You close the lid and the screen goes off, you press the power button and the machine shuts down, but what’s actually happening here?  Let me explain what each does.

If you Shut Down your PC, windows sends a signal to every program running to prompt to save the data and then close down, Windows itself then closes all of it’s active files, and sends the shutdown message to the PC to turn itself off.  when you power on from a shutdown state, this is called a cold boot, all files are freshly loaded, the memory starts from blank, your machine will be as good as it’s ever going to be after a cold boot.

Sleep is a state where every window you have open, every file that you are working on is kept in memory, the display is powered off, but power still runs to your cpu, your memory and some other parts of your machine.  If you’ve read my PC guide, you’ll know that RAM is non permanat storage, so when it’s not receiving power it’s wiped clean. this is why the power is kept to your RAM.  when you power the machine up from a Sleep state it will appear ready almost instantly.  But remember your machine’s ram has not been reset so if you have any memory that hasn’t been fully cleared from programs you were running, it will be in the same state it was previously.

Hibernation is where your computer takes everything you have in RAM, all programs, data, every single window you have open and their locations etc, and copies the entire lot onto the hard drive and then shuts down.  When you power back on, it copies it all back from the hard disk to RAM so Windows loads back to where it was.

So what are they for then?  Well, Sleep is for when you’re just leaving the machine for a few minutes, and want to preserve some battery life,  Hibernate is when you’re away from the computer a long time, it means your PC won’t use any battery power at all.  Hibernate takes less time to boot than booting after shutting down does.  Most notebooks that are about to run out of battery will automatically hibernate when there’s only a small amount of battery left to give you a chance of keeping any unsaved files.  But the problem with Hibernation is that the file that’s copied onto your hard disk may become corrupted.  If that happens, you’ve lost whatever you were working on.  So hibernation is good to use, but remember to save your work.  And shutting down your machine is the best way to keep it clear of memory hogging programs and temporary files cluttering up your hard drive.

What to use is up to you,  but remember the drawbacks, sleep still uses battery, hibernate may fail and you end up losing what your working on, and shut down, the slowest yet most reliable of the 3….

If you have any questions feel free to mail me on zygomorphic@webdesignwhim.com

Well I started to write an article on setting up a home network, and started to explain some of the terms, and it seemed to spiral out of control, so here is a lots of the terms explained and the actual guide will come later.

Modem.

In the old days, this connected to your phone line and Modulated and Demodulated the data you were sending and receiving.  In short?  It changed your digital data into sound.  this sound was then sent over the phone line and a modem at the other end converted it back into data.  Nowadays what people call modems are ADSL and Cable Modems.

NIC

Network Interface Card, the bit of equipment that allows you to connect to a network.  Can be either wired or Wireless.  Most laptops nowadays come with both,  most desktop machines will just have wired, but some will come with wireless.

Wireless – 802.11 a/b/g/n

802.11 is the world standard for wireless ethernet the a/b/g/n are all variants of it.

802.11a is wireless running on the 5 Gigahertz (Ghz) band.  It was initially used in the US and Japan, and allowed data transfer of 54 Megabits per second (Mbit/s)

802.11b was the european standard which ran on the 2.4Ghz band.  it only got up to speeds of 11 Mbit/s, but was then replaced by 802.11g.  The G standard also ran on the 2.4Ghz band but achieved similar speeds to 802.11a of 54 Mbit/s  This is the most common wireless in use today in Europe

802.11n is the new standard.  as of writing It’s still not been formally accepted as the stadarD, but the draft standard is what all 802.11n devices are compatable with.  802.11n gives a theoretical maximum of 600 Mbit/s, but in the real world will probably rarely get over 150 Mbit/s for quite a while due to the expense of the equipment.  If you look at a router for 802.11a b or g, there may be one or two antennae, but both send and receive the same data.  With 802.11n, there can be up to 5 antenna on the router, and each can receive different data, and the wireless card on your pc can also have multiple antenna, can’t for the life of me remember how many…

Ethernet/RJ45/Cat 5

The standard cabling type for a network.  pre ethernet there were network types called token ring and BNC, but these are consigned to history books now.  RJ45 is what the connector is called and category 5 aka cat 5 is the type of cable itself. Cat 6 is an improved version which is available now, but is still expensive at the moment.  cat 5 cables are designed for 100 Mbit networks and Cat 6 are designed for Gigabit ones.

Switch/Hub

A hub is simply a connection point for multiple devices.  If you have 2 computers connected via ethernet to a hub, they can talk to each other.  They still need a language like tcp/ip so that they can find each other and transfer data.  A switch is simply an intellegent hub.  Assume you have a 4 port hub with 4 computers connected.  computer a is trying to talk to computer d.  it will send out the data it is sending and the hub will send the same data to computers b c and d trying to find the right place.  a switch remembers where the computers are and knows that it only needs to send the data to the correct place to reach computer d.

Router.

The heart of a network.  Networks will work without routers, but using routers simplify things.  The whole internet is just a worldwide network of routers.  a large bunch of servers connected to routers have the content like webpages, but it’s the routers that make it all happen.  hmmm  I think i’ll come back to routers after tcp/ip….

TCP/IP

Transport control Protocol/Internet Protocol.  Data is the words we speak, TCP/IP is the language.  Every machine connected to the internet has an IP address of some shape form or fashion.  If your computer is part of a network at home you may very well have an address of 192.168.0.2 or something like that.  The unique IP address for your internet connection will be on your router, and will be one of a range assigned to your ISP to give out to customers.

ISP

Internet Service provider.  Companies who supply their customers with internet access.  Most ISPs will only supply one type of broadband, either DSL or Cable.

Bandwidth

The amount of data you can transfer through a connection.  for example a 10 Mbit line can transfer 10 million bits per second.  remember that most computer terms are in bytes, not bits.  this makes things confusing. since there are 8 bits to one byte, an MP3 song which is 3 megabytes in size is 24 million bits

DSL Broadband

Digital subscriber Line. Broadband over the telephone network. In the UK we have ADSL which is asynchronous, some countrys supply sdsl, synchronous.  ADSL simply means that upload and download speeds are not equal so a 10 Mbit download speed may only have a 600ish Kbit upload speed (as is the case on my line)

ADSL Filter/Line Filter

This is a small box that you stick in your home phone line when you have DSL.  the purpose of this bos is to seperate the DSL and Voice signals on your line.  It directs the DSL upload and download signals higher in the bandwith range, and limits the voice signal to low down in the range so the voice signal won’t effect the DSL signal.  this is why every device connected to your phone line, like fax machines, satellite TV boxes and telephones all need a filter between them and the phone line

Cable Broadband

Broadband over the Coaxial television system.  Tends to get higher speeds than DSL, but has the disadvantage that everyone in the local area will take a share of the bandwidth so at peak times it can slow down dramatically

There was more here I wanted to go into, but that’ll have to wait for another time.  It’s late and I’m tired

If you have any questions feel free to mail me on zygomorphic@webdesignwhim.com

* This article is written by Zygomorphic of www.webdesignwhim.com Please do not copy our material and portray it as your own work. Feel free to post our articles but only without removing this notice and stating where you got this article from. Thank you *

It’s quite hard today to buy a Laptop.  You can get Notebooks, but very few laptops.  And I’m not talking about Netbooks here, they’re a totally different kettle of fish.  But what’s the difference?  Laptops can be used on a Lap, Notebooks can’t.  Obvious really isn’t it?  There was a stage where every portable computer was termed a Laptop.  But then Machines got faster, and thus generated more heat, and so became too hot to be used on a Lap.  Notebooks are designed to be used on a hard flat surface.  See those little feet on the bottom?  They’re not there for decoration, they’re there to raise the base of the machine off the table to allow air to circulate out of the big vent on the bottom near the CPU fan.  When you put it on your leg, you usually block that vent causing the unit to overheat, and this can cause damage to the CPU, can melt the plastic of the case, and in more serious cases can burn you.

For peace of mind, I recommend a tea tray, you know the type with the bean bag base that is meant for having TV dinners?  Makes a nice base for a notebook to sit on if you insist on having it on your lap.

If you have any questions feel free to mail me on zygomorphic@webdesignwhim.com

I scream inwards when I hear people calling a Laptop AC adapter a charger.  It’s just a personal thing for me.  You can take the battery out of a Laptop and it will still work on AC.  So hang on, what’s it charging?  A charger only does 1 thing, charges a battery, but an AC adapter allows a DC device to run on AC current.  While the device is running, it may very well be charging the battery, but inherently it’s purpose is to allow the device to run.  So next time you hear someone refer to a Laptop AC adapter as a charger, be sure to point them out to this article to correct their illusion.

If you have any questions feel free to mail me on zygomorphic@webdesignwhim.com

For my first techy post, I’d like to introduce you to someone who you are already well acquainted with.  Your computer.

It’s frustrating when it doesn’t work, I’m sure you’ve threatened to throw it out the window more than once, It does things you don’t want it to, and won’t do things you do.  But if you’re like many people today, you’d be totally lost without it.  In the past, you got your morning post to read while eating breakfast, and now you check your email and your favourite sites.  but what goes on inside that whirring box you have under the table that you either kick by accident when sitting down or use as a coffee cup holder/footrest?  Maybe you have a laptop or netbook instead of a desktop pc, the technology is inherently the same with a few changes for weight and power consumption primarily

Inside that tower you have some standard components.  A hard drive, an optical drive, a motherboard, a CPU, some way to cool the CPU, some memory, a power supply, some way of outputting to a display and a bunch of cables.

The heart of your machine is the CPU or Central Processing Unit, more commonly known as the Processor.

Depending on what machine type you have this will change, there are desktop versions, laptop versions, netbook versions and server versions of these.  Having said that, some laptops will have desktop versions, and vice versa.  The main differences between Laptop and Desktop CPUs are the power consumption.  Desktop CPUs will generally run at full speed most of the time, but laptop CPUS will be slower to generate less heat and will throttle themselves when running on battery to make the battery last longer.  The CPU is what makes decisions in your machine.

Your hard drive is where all your files and programs are kept.  It’s called permanent storage.  When you switch on your pc, the computer looks to the boot sector of your hard disk, and loads whatever it finds there.  It takes whatever files it needs and loads them for the Operating system to get you up and running.  When you save files, you’re saving them to the hard disk.  The hard disk is some platters, often coated aluminium that spin around at a huge speed.  Laptop hard drives used to spin at 4200 revolutions per minute (RPM) and desktops used to do 5,400 RPM, but now desktop drives are available that spin at 10,000 rpm and server drives spin at up to 15,000 rpm. the platters spin on a spindle and each side of each platter has a head on a movable arm.  This head moves over the surface of the disk at incredible speed reading and writing to the platter. when I say reading and writing, what it is actually doing, it’s really magnetising or de-magnetising the relevant parts of the disk.  a magnetised part equates to a “1″ and a demagnetised is a “0″ the computer reads this and it’s programming tells it how to understand this and to show you what it’s programmed to do.  this tends to be the most vulnerable part of your computer due to the speeds the disk is spinning.  hard drives are airtight and are made in a dust free environment.  if a speck of dust gets into a hard drive it could get between the platter and the head and cause the head to impact on the platter.  If this happens the hard drive surface is damaged and will result in file corruption or total loss of the whole drive.  for this reason it’s a really bad idea to move a machine when it’s on, as even though hard drives have shock protection built in, it’s easy to drop it and bye bye data.  People often refer to the hard drive as memory and get the 2 confused.

Your memory is non permanent storage.  It’s also called RAM, Random Access Memory.  How do I describe what the Ram in your machine does?  It acts like a buffer.  Your CPU does things very fast, much faster than your hard drive can read or write.  When you load something like a program from your hard disk, it gets copied into the RAM, and the RAM then feeds the data to the CPU as required.  All running programs are loaded into the RAM also as running from the Hard drive would be painfully slow.  Every time you restart your computer the ram is wiped clean, hence the non-permanent aspect of it.  If for example you’re writing a letter in a Word processing package, that is being done in RAM.  when you click save, it takes a copy of what you have in ram and writes it to the hard drive for permanent storage.

Your power supply unit (PSU) takes your normal 240 or 100 volt electricity supply, and transforms it to the voltages that your pc uses. Many people get the largest PSU they can, but this is really unnecessary.  PSU’s are rated in watts, each device in your computer will use a certain amount of watts.  for example a hard disk will generally require between 15 and 30 watts, your CPU will need anywhere between 50 and 105 watts depending on what type it is.  An average machine with a graphics card will use about 400 Watts so installing a 500 watt psu is all that’s needed. Having that machine with a 1000 watt PSU is just burning electricity.

Your motherboard is what holds all those components together.  The CPU and RAM are mounted on this in their respective sockets, the hard drive is plugged into the correct port, and is powered from the PSU.  The PSU is also plugged into the motherboard to supply it, the CPU and RAM their power.  The motherboard has Bridges, it provides the link between the CPU and the ram, it also uses the Northbridge and South bridge to connect to external things like the PCI bus, the ethernet controller, the audio chip, the USB BUS and others.  What are they I hear you scream…They’re for another day I’m afraid.

If you have any questions feel free to mail me on zygomorphic@webdesignwhim.com

* with apologies to Douglas Adams for nicking the title

* This article is written by Zygomorphic of www.webdesignwhim.com Please do not copy our material and portray it as your own work. Feel free to post our articles but only without removing this notice and stating where you got this article from. Thank you *