Tuesday, 1 January 2019

Plugging Things in and Pulling Things Out - Upgrading

There was a time in the distant past (like the 90s and early 2000s) when we had this desire to upgrade and expand our computers. Well, maybe that is still the case, but I guess that also related to those of us who were hard core gamers and always wanted a decent computer to play all the top notch games, particularly if they required graphics rendering. This doesn't seemed to be as much of the case these days, in that it is really only those incredibly dedicated gamers that want the top notch machine, while many of us are happy with a computer that works (and in my case simply runs a c64 emulator or dos box).

Anyway system and peripheral expansion is still something that needs to be considered, even though desktops really only exist for special purposes such as video creating and game playing - there really isn't a huge scope for expanding laptops, and they are so fiddly that there really isn't a point. Moreso, pretty much all of the external devices use USB these days, however one thing we need to remember is that not all USB wires are the same, and even though USB is, well, universal, there are still alternatives out there, such as fire wire.

Another thing that we need to consider are inboard connectors such as ATA, SATA, and SCSI. Oh, and we can't forget wifi and bluetooth, which are wireless protocols for expansion.

USB, Firewire, and Thunderbolt

Basically these are three different types of cables, with advantages and disadvantages. Sure, USB is everywhere, but there is still some scope for using Firewire and Thunderbolt. First Thunderbolt, which is a networking protocol that was developed by Intel. Initially it used its own connectors, but the latest iteration means that it can be connected to a USB-C connector. This is how Thunderbolt is currently being marketed:

Honestly, I wouldn't go by what the advertisement tells you. In fact that is something you should never do, but rather go by what other people have reported. The other thing is that the maximum they give you is always a theoretical maximum and can only be achieved in the rarest of circumstances.

Now, many of these protocols are measured at bits per second, or bps. So, when working out how much time it will take to actually transfer data we need to do some maths. Once again, remember, we can't use the maximum rate because it never operates at this speed. However, with this in mind, lets see how long it takes for a friend of ours - Jim - to copy 200 photos from, say, his camera to his hard drive.

Now, Each of these photos comprise of 3 megapixels, and each pixel comprises of 3 bytes (one each for red, green, and blue). So, we need to work out the size of these photos. 3 megapixels is 3000 pixels, at three bits each gives us 9000 bytes. Now, there are 200 of these photos, so that gives us a total size of 1 800 000 bytes, which translates to 1.8 GB (remember capital B for bytes, small b for bits - don't get confused).

So, let us use a USB 'superspeed' transfer first, and say that it is operating at 60% efficiency. So, the USB transfers data at 5 Gbps (Giga-bits per second), but it only operating at 60% efficiency, so that us 5 x 0.6 = 3 Gbps. Now, we have 1.8 GB of data to transfer, so converting the transfer speed into bytes we need to divide it by 8 (8 bits in a byte), which gives us 0.375 GB/s. Now, divide the size of the data by the transfer speed, so we have 1.8/0.375 which gives us 4.8 seconds. Not long.
Well, lets see how well it works with Firewire (and Apple development). Firewire 400 transfers at 400 Mbps, and say it is a little better and operates at 80% efficiency. So:

400*0.8 = 320 Mbps.

Now we need to convert the transfer speed into bytes:

320/8 = 40 MB/s.

To make it simpler, let us convert the data size into Megabytes:

1.8 * 1000 = 1800 MBs.

So, the next step is to divide the size of the data by the transfer speed, so:

1800/40 = 45s.

A lot slower isn't it?

Okay, now, lets through another problem into the mix. Say as a part of that transfer Jim is also transferring over a wireless network whose transfer speed is 60 Mbs and is operating at 25% efficiency?

So, first we work out the actual transfer speed:

60 x 0.25 = 15 Mb/s

Convert the transfer speed into bytes:

15/8 = 1.875 MB/s.

We already know the size of the data in Megabytes, which is 1800 MB, so we divide the data by the transfer speed:

1800/1.875 = 960s divided by 60 (60 seconds in a minute) gives us 16 minutes. Well, it seems that this is going to cause a bit of a bottle neck. However, once we had worked out the actual transfer speed, we could already compare that with what we already had so we didn't really needed to go further, unless we actually wanted to know how long it would take.

So, now the question comes down as to why don't they operate at their peak speeds. Well, there is one obvious answer - marketing. Isn't it the case that advertisers are always going to talk their product up so that it appears to be better than it really is. Honestly, while there is always a desire to see 'truth' in advertising it isn't something that you are always going to get.

But, there are other factors as well, such are wear and tear, and environmental conditions such as interference, or even just a plain hot day. The other thing is that not all bandwidth can simply be used for data, it needs to be shared with other things. Remember that USB cables also work to power some of these devices, and some bandwidth also needs to be reserved for other factors.

System Expansion

Okay, there was a time when motherboards were really basic, which meant if you wanted graphics then you needed a graphics card. In fact if you wanted Wi-Fi, or even to hook your computer up to a network you also needed a special card. Actually, come to think of it, I had to go down to Officeworks a few months back to purchase a new wifi card because my previous one had pretty much gone kaput (it's actually great using that word in its original context).

However, what is better - onboard integration or simply adding a new card. Well, my motherboard has it's own video port, but my Dad included a video card when he built the system, no doubt for 3D rendering needs (which I suspect such an old motherboard really couldn't handle). However, by integrating these systems into the motherboard, it actually frees up the PCI (which stands for peripheral component interconnect) slots for other things. Take the wifi card for example - they are so ubiquitous these days, that it simply is a waste to have to use one for a wifi, or even a network, card. There is also the issue of speed, but the thing is that if you want better graphics that your motherboard can supply, then you are going to look for other options.

Now onto the connectors. The main way peripheral devices are connected is either through PCI or ATA. ATA stands for Advanced Technology Attachment, and originally it would run in parallel. Actually, my storage devices are connected to the motherboard using ATA cables, and honestly, they are an absolute pain in that they pretty much take up most of the space inside the box - if you actually want to do anything you literally have to remove them. Another thing with the PATA cables is that they work on a bus topography, meaning that multiple devices could be connected to the same cable. However, there was no scope for simultaneous usage. In fact, you had to label one of the drives 'the master' and the other 'the slave' (blame the computer scientists, not me).

Well, they've been replaced with what is called SATA, or Serial ATA. SATA uses thinner cables, and also operate point to point, which means that separate cables are used for the devices (though I suspect that the mother board then needs to be configured to accept multiple devices. Another thing is that they also allow for hotswapping. As for speed, well, they're pretty fast, with the third generation transferring up to 6 Gb/s.

With regards to other components, we have PCI (peripheral component interconnet), and AGP (Advanced Graphics Port). PCI is what is termed as a 'legacy' component, which basically means that while devices aren't made for them anymore, they are still kept because there are still a lot of older devices out there. In fact many motherboards will still have a single PCI slot on them. They tended to be configured in a bus topology and their speeds were around 133 MB/s for both read and write.

The AGP is a later addition that basically connects straight to the CPU (or the northbridge, which you generally don't find in modern computers, but basically was the gateway between the CPU and the rest of the computer - the memory would go directly into the Northbridge, as did the graphics card, which the rest had to go through the southbridge and then into the northbridge). This pretty much speeds up the graphics cards because they aren't fighting over bandwidth with other peripherals, whether they be inside, or outside, the computer.

Now, the architecture is slightly different in that we have the PCI express standard. This is also point to point, but slightly different. While they don't use the same lanes, they do share lanes. One will be labelled, say PCIe 32, which means the card plugged in there can use 32 lanes. The next one is labelled PCIe 16. Now, if you also have a card plugged into the PCIe 16, the card in the 32 lane slot can only use 16 of those lanes, because the other card is using the other 16. There are also PCIe 8 slots, but they don't actually share lanes with those two (but rather with other slots).

Bluetooth & Wifi

At first I though bluetooth was a thing of the past because, well, I never use it. Then again that's because I don't have an earpiece for my phone, nor to I have one of those fancy new cars. Actually, I don't even have a car. As it turns out blue tooth is still regularly used. In fact I used it to connect a wireless keyboard to my tablet because it is so much easier to write on a keyboard than it is on those stupid screen keyboards.

Basically you connect devices by pairing them. Actually, there was a time when people would use bluetooth to pick up other people in the bar, though I sort of wonder how they actually knew who was who, especially since you couldn't use it to send messages. What you could use it for was data transfer, and I would play around with it with a friend by pairing our devices and trading songs.

Now, not all devices are the same, and bluetooth does operate on different frequencies. The other thing is that bluetooth doesn't have a huge range, from less than a meter to about 100 meters. These devices are divided into classes, namely class 3 being the shortest and class 1 being the longest. The transmit power is also less for the class three as opposed to the class one. The other thing to be aware of is that if you want to communicate with a class 1 device at a distance you also need a class 1 device, however that doesn't matter when you come into the class 2 range. Most headsets and mobile devices are class 2. Also, if you have devices of different classes, they will tend to revert to the weaker class.

The other thing is that bluetooth is made up of profiles, as such:

Advanced Audio Distribution Profile (A2DP): This is usually used for the headphones due to the high quality of the audio.
Cordless Telephony Profile (CTP): If you have a cordless phone, then this is the profile that is used to connect the phone to the base station (I have such a phone, but I never use it).

Dial-up Networking (DUN): This is used to turn your phone into a modem, though I generally just use the the 'wireless hotspot' function.

File Transfer Profile (FTP): This is the protocol that my mate and I would use to transfer songs.

Hands-Free Profile (HFP): This is basically used in those fancy, bluetooth enabled, cars (though I could never get it to work when I was actually driving one of those cars).

Human Interface Device (HID): That keyboard I told you about? It uses this profile.

Headset (HSP): This is the profile for those earpieces you see about the place.
LAN Access (LSP): This is another way for turning your phone into a modem.

I mentioned that you have to pair bluetooth devices, and that is correct. However, when you have bluetooth enabled, if there is the ability to pair, then it will connect. However, if it does connect then both ends need to give permission to pair. This is why when you turn bluetooth on, you can see (or you used to be able to see, since people don't leave their bluetooth on anymore) the other devices within range. This pairing is not always the case though, such as with keyboards where you can realistically only pair from one end.

As for Wifi, well that works on what is known as the 802.11 standard, though this is broken up into a number of standards, such as 802.11a, 802.11ac, 802.11b/g/n. I'm sure you get the picture.

Anyway, the letters at the end pretty much tell you the generation, with the latest being the ac, which was developed in 2013. Wifi has become faster over time, but in the early days (around b, which was 1999) it had problems with interference from other devices. There were also issues with it being blocked by, well, walls.

Wifi operates on one of two frequencies, being 2.5 Ghz and 5 Ghz. The latest rendition operates on the 5 Ghz frequencies. 2.5 offered the better range, however the problem was that that frequency is actually quite crowded so you would suffer from interference. 5 Ghz doesn't have as greater range, but it does offer much better throughput. Also, there isn't as much interference.

Another thing to consider when discussing frequency is channel width, and this is measured, not surprisingly, in hertz (usually Mhz). This is basically the width of the spectrum that has been allocated to the device. It also determines how large of a pipe there is to channel data. The problem with channels that are too wide is that they are more subject to interference from other devices.

A final thing to touch on here involves Beamforming. Initially wifi would simply blast waves away from the device in all directions, however modern technology means that when a device connects to the wifi router, what will happen is that the router will beam the signal to the device, thus created a much stronger connection.

Source www,birate.com

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Plugging Things in and Pulling Things Out - Upgrading by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

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