Mod:laptop

See also: Laptop use, Windows mode, Programs, Module 1, Module 2, Module 3,Writing up

Using a laptop for the course

This section describes how to use your course laptop running the Microsoft Windows or Linux operating system, and what to do if you need technical assistance with it.

We trust you to treat the laptops supplied for this course with care. If a laptop is returned with damage beyond "reasonable wear", you will be liable for a flat fee of £50. Seriously damaged or lost laptops will be evaluated on a case by case basis: you will be liable for the cost of purchasing a replacement laptop, although if documentation is provided, extenuating circumstances will be taken into account. Please note that it is a requirement for graduation that any lost or damaged laptop is paid for (similarly for library debts).

The laptop contains in one simple and portable package all the software you will need to complete this lab; however students are not obliged to accept the laptop under the conditions we have set, you can use the desktop computers provided in the study and computer room areas (although these are on a first come-first served basis). Potential lab grades will not be decreased in any significant way by not taking a laptop.

Course Laptop Pickup and configuration

1. The first day of the course will include acquiring the course laptop, and familiarizing yourself with its use.
2. Of particular importance is the need to connect it at least once to a wired network access point in the department, and to log yourself in whilst it is connected. The most convenient location for doing this might be the study area on level 2, or the adjacent tutorial rooms. You will need a patch cable for the purpose (one such should be in the laptop bag issued to you), which is connected at the rear-right of the laptop. Once connected, press the power button on the top left of the keyboard.
3. Windows XP loads at startup. After the boot is complete, log yourself in, ensuring that the domain IC is selected. This should progress as per any desktop login. When you log out from this session, all your credentials as cached on the laptop. Should you wish to log in again, but this time with no wired connection, your cached details will be used to enable you to access applications and documents you might have stored on the laptop hard disk. You will also require this cached profile if you want to use your laptop online at home, or outside the department/college.
4. We suggest you use the laptop in wired mode on College premises if a socket for your patch-lead is available. If you do want to use wireless, configure it as follows:
   1. Ensure the Wireless card is on (blue light above the keyboard; if it's not blue, press the button to switch it on). You will need to have rebooted the machine once after you first ever logged in on a wired connection before proceeding to the next step.
   2. The Wireless client you will use is called XSupplicant (Microsoft's own client has issues). XSupplicant is invoked from the system tray on the bottom right of the task bar. Right click and select quick connect
   3. Select the Imperial-WPA network (or if at home, your own local network) and provide this with your College login ID and password. It may take a few seconds (up to ~20) for connection to be established. If some some reason it loses the connection or doesn't connect properly you might need to try again.
   4. If you put the laptop into hibernate mode (by closing the lid and leaving it closed for ~10 seconds), it may take a little while to re-establish the connection when you re-open the laptop.
5. If you use Firefox as your browser and try to connect to the chemistry wiki, you may get a Secure Connection Failed page appear, just click on the "Or you can add an exception..." link and click the "Add Exception" button, then "Get Certificate" and then "Confirm Security Exception". You should then be given access to the chemistry wiki site.

Laptop use and file storage whilst at Imperial

1. Your laptop should run for about 6 hours from a full charge. If you do need to charge it during a working day, please do so in the study or the tutorial rooms on level 2. If you need to store the laptop temporarily during the day, there will be a rack of cube-shaped storage boxes in the study area, and you will be issued with a personalised key when you pick up the laptop.
2. If you are working in College, and have the laptop online (via either a wired patch lead or the WiFi), then store everything in the usual place (H:). Alternatively, you will find a drive labelled E:, which is in fact part of the hard drive on the system. You should use this if you are offline. This drive has a total capacity of around 50 Gbytes (compared to 500 Mbyte for drive H:) so you can also use it to store very large files. Be aware however that whilst drive H: is backed up each night, drive E: will not be backed up at all (so if the laptop fails, or is stolen, you will lose everything). We suggest you store your key results on both drives!

How fast is the laptop?

Computational chemistry modelling varies wildly in the amount of computer time need. Thus most molecular mechanics and semi-empirical MO calculations take just seconds, or a minute or so. These are all done on your laptop. The ab initio and DFT procedures can be much more time consuming, and now the issue arises of whether they should even be attempted on your laptop. The particular model you are using is a low-power unit, designed so that the unit is lightweight, and that the battery charge lasts for an entire working day. This means that the processors (of which there are two) are actually relatively slow by modern standards. They are nevertheless fast enough for you to attempt Gaussian calculations on small molecules (typically the size of eg cyclohexane). If you do attempt such a calculation, you will immediately notice that the fans on the laptop kick in very soon, and the unit may get quite hot! For this reason, you should never attempt to run such a calculation for much more than about 1 hour. Under no circumstances should you attempt to leave it running e.g. overnight! If it turns out you do need to run for > 1 hour, then submit to the batch subsystem (SCAN) we have set up for you to use. Not only are the computers you will use there at least 20 times faster than the laptop, such jobs also do not compromise your ability to continue using the laptop, and they also let you run multiple jobs concurrently.

Technical Help

1. If you are having problems with the laptop, take it to the ICT support desks, in either Sherfield level 4, or Room 135 in chemistry C1. IMPORTANT A small number of systems might show abnormal instability. This manifests with unexpected and total freezes 3-4 times a day or more. If you experience this, do not simply wait for the problem to resolve itself, but arrange to have it swapped for a hot spare. Sometimes hardware faults (or e.g. memory modules that might have become unseated, or simply faulty) will cause this, and the system will probably benefit from a thorough checkout.
2. You may also wish to keep an eye out on the late breaking news page for general updates, and the discussion areas for Module 1, module 2 and module 3 where people document their experiences, suggest bug fixes etc.

Laptop use at home

The advantage of having your personalized laboratory is that you can complete experiments wherever you wish, and not just in the Imperial College precincts. Proceed as follows:

1. You will have to go online at home. Since this varies according to the ISP service you have, you will have to arrange this yourself (via your ISP if necessary). If you are using WiFi at home, configure it as per above.
2. 
   In order to edit the Wiki for your project, you will need to establish a VPN connection as part of this process. An icon on the desktop is available for this purpose.
   1. To mount your drive H:, find out its network address: Home Directory Location. Armed with this information, follow the instructions in Home directory mounts
   2. To mount drive L (the area Linux uses when connected to a network), assume that the network address is \\icnfs-ch.cc.ic.ac.uk\your-login-id and proceed as above.
3. You can also use your own laptop (as opposed to the loan laptop), but please be aware that much of the software installed on the course laptop described in the previous section may be missing since the site licenses we have for it will not apply to your personal laptop. There is one exception to this; the site license for ChemBio3D does allow any student with a valid Imperial College email account to install it on their own laptop. To invoke this license, connect to this site and follow the instructions. This license will last for only one year.

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See also: Laptop use, Windows mode, Programs, Module 1, Module 2, Module 3,Writing up