Technology Tales

Adding workspaces to Windows

One of the nice things about working with Linux/UNIX is that you can organise your open applications so that they are open in different workspaces or virtual desktops. When I return to working on Windows, having everything open on the same desktop is something that I find less tidy. However, there is an open source application that adds virtual desktops to Windows and very useful it is too.

It is called VirtuaWin and it adds an icon to the taskbar for switching between workspaces when it is running; there might be a bit of tweaking to be done for it to stay visible all of the time though. You can have it as a startup application in the same way that you have your security software and I have been using it smoothly on both Windows XP and Windows 7 running in VirtualBox virtual machines. Insofar as I have seen it, you can have as many workspaces as you want and switching from one to another is achievable using keyboard shortcuts. Using CTRL, ALT and one of the arrow keys does it for me but you can set up your own. All in all, it’s a small download that brings a little sense of Windows desktop computing.

Unfinished business

If you’ve been here before, you’ll notice that the first rendition of the new look for this place has been introduced. It is based upon the intention WordPress theme but more work is needed before it looks as tidy as I’d like it. That’ll take a little while and improvements will come gradually but I hope that the new design is pleasing even at this point in time. At the very least, it looks natty to my eyes though there are little bits and pieces that I have ended up leaving behind for now. Even so, it gives me a modern menu at the top of every page so I’m far from disappointed. In any case, I don’t mind doing some extra tinkering.

ERROR 22-322: Syntax error, expecting one of the following: a name, *.

This is one of the classic SAS errors that you can get from PROC SQL and it can be thrown by a number of things. Missing out a comma in a list of variables on a SELECT statement is one situation that will do it, as will having an extraneous one. As I discovered recently, an ill-defined SAS function nesting like LEFT(TRIM(PERIOD,BEST.)) will have the same effect; notice the missing PUT function in the example. The latter surprised me because I might have expected something more descriptive for this as would be the case in data step code. In the event, it took some looking before the problem hit me because it’s amazing how blind you can become to things that are staring you in the face. Familiarity really can make you pay less attention.

ERROR: Invalid value for width specified – width out of range

This could be the beginning of a series on error messages from PROC SQL that may appear unclear to a programmer more familiar with Data Step. The cause of my getting the message that heads this posting is that there was a numeric variable with a length less that the default of 8, not the best of situations. Sadly, the message doesn’t pin point the affected variable so it took some commenting out of pieces of code before I found the cause of the problem. That’s never to say that PROC SQL does not have debugging functionality in the form of FEEDBACK, NOEXEC, _METHOD and _TREE options on the PROC SQL line itself or the validation statement but neither of these seemed to help in this instance. Still, they’re worth keeping in mind for the future as is SAS Institute’s own page on SQL query debugging. Of course, now that I know what might be the cause, a simple PROC SQL report using the dictionary tables should help. The following code should do the needful:

proc sql;
select memname, name, type, length
from dictionary.columns
where libname="DATA" and type="num" and length ne 8;
quit;

If all else fails…

Two problems have come my way that were resolved by removing configuration files and going again. Both affected Linux installations that I have. The Ubuntu installation on my main PC is working well but I ran into trouble starting up NetBeans 6.8. No GUI would ever appear but taking away the .netbeans folder from my home area allowed a fresh start with the IDE starting up as it should. To date, not all the various projects that I have are restored, but that can be done as I go along. Plugins for PHP development needing reinstatement, but that was another easy thing to achieve; just go to Tools -> Plugins on the menus and work with the dialogue box that appears to download and install the needful.

The inspiration for taking the configuration folder from the home area came from needing to address a misadventure with a Debian VM. Perhaps foolishly, I went using gconf-editor on there and messed up the appearance of the terminal window with whatever change I made. Getting rid of the .gconf folder restored order with its recreation by the system. Next time, remembering what changes have been made and reversing them might be the best course of action…

Upgrading to Fedora 13

After having a spin of Fedora’s latest in a Virtualbox virtual machine on my main home PC, I decided to upgrade my Fedora box. First, I needed to battle imperfect Internet speeds to get an ISO image that I could burn to a DVD. Once that was in place, I rebooted the Fedora machine using the DVD and chose the upgrade option to avoid bringing a major upheaval upon myself. You need the full DVD for this because only a full installation is available from Live ISO images and CD’s.

All was graphical easiness and I got back into Fedora again without a hitch. Along with other bits and pieces, MySQL, PHP and Apache are working as before. If there was any glitch, it was with Netbeans 6.8 because the upgrade from the previous version didn’t seem to be a complete as hoped. However, it was nothing that an update of the open source variant of Java and Netbeans itself couldn’t resolve. There may have been untidy poking around before the solution was found but all has been well since then.

Solving an upgrade hitch en route to Ubuntu 10.04

After waiting until after a weekend in the Isle of Man, I got to upgrading my main home PC to Ubuntu 10.04. Before the weekend away, I had been updating a 10.04 installation on an old spare PC and that worked fine so the prospects were good for a similar changeover on the main box. That may have been so but breaking a computer hardly is the perfect complement to a getaway.

So as to keep the level of disruption to a minimum, I opted for an in-situ upgrade. The download was left to complete in its own good time and I returned to attend to installation messages asking me if I wished to retain old logs files for the likes of Apache. When the system asked for reboot at the end of the sequence of package downloading, installation and removal, I was ready to leave it do the needful.

However, I met with a hitch when the machine restarted: it couldn’t find the root drive. Live CD’s were pressed into service to shed light on what had happened. First up was an old disc for 9.10 before one for 10.04 Beta 1 was used. That identified a difference between the two that was to prove to be the cause of what I was seeing. 10.04 uses /dev/hd*# (/dev/hda1 is an example) nomenclature for everything including software RAID arrays (“fakeraid”). 9.10 used the /dev/mapper/sil_**************# convention for two of my drives and I get the impression that the names differ according to the chipset that is used.

During the upgrade process, the one thing that was missed was the changeover from /dev/mapper/sil_**************# to /dev/hd*# in the appropriate places in /boot/grub/menu.lst; look for the lines starting with the word kernel. When I did what the operating system forgot, I was greeted by a screen telling of the progress of checks on one of the system’s disks. That process took a while but a login screen followed and I had my desktop much as before. The only other thing that I had to do was run gconf-editor from the terminal to send the title bar buttons to the right where I am accustomed to having them. Since then, I have been working away as before.

Some may decry the lack of change (ImageMagick and UFRaw could do with working together much faster, though) but I’m not complaining; the rough of 9.10 drilled that into me. Nevertheless, I am left wondering how many are getting tripped up by what I encountered, even if it means that Palimpsest (what Ubuntu calls Disk Utility) looks much tidier than it did. Could the same thing be affecting /etc/fstab too? The reason that I don’t know the answer to that question is that I changed all hard disk drive references to UUID a while ago but it’s another place to look if the GRUB change isn’t fixing things for you. If my memory isn’t failing me, I seem to remember seeing /dev/mapper/sil_**************# drive names in there too.

Removing a column from a MySQL data table

My trying out WordPress 3.0 in advance of its final release has brought me errors on the links management page. After a spot of poking around the TRAC, I found that the bug already has been reported and that the cause is an extraneous column in the *_links table called link_category. The change in taxonomy handling over the years seems to have made it redundant so I removed the said column from the database using a command like the following from both the MySQL command line and MySQL Query Browser:

alter table wordpress.wp_links drop link_category;

That seems to have made those errors go away and I hop that their upgrade code takes care of this before WordPress 3.0 is let loose of the general blogging public. Taking out the coding brittleness would do too.

Reading data into SAS using the EXCEL and PCFILES library engines

Recently, I had the opportunity to have a look at the Excel library engine again because I need to read Excel data into SAS. You need SAS Access for PC Files licensed for it to but it does simplify the process of getting data from spreadsheets into SAS. It all revolves around setting up a library pointing at the Excel file using the Excel engine. The result is that every worksheet in the file is treated like a SAS dataset even if there names contain characters that SAS considers invalid for dataset names. The way around that is to enclose the worksheet name in single quotes with the letter n straight after the closing quote, much in the same way as you’d read in text strings as SAS date values (’04MAR2010’d, for example). In order to make all of this more, I have added some example code below.

libname testxl excel 'c:\test.xls';

data test;
set testxl.'sheet1$'n;
run;

All of the above does apply to SAS on Windows (I have used it successfully in 9.1.3 and 9.2) but there seems to be a way of using the same type of thing on UNIX too. Again, SAS Access for PC Files is needed as well as a SAS PC Files server on an available Windows machine and it is the PCFILES engine that is specified. While I cannot say that I have had the chance to see it working in practice but seeing it described in SAS Online Documentation corrected my previous misimpressions about the UNIX variant of SAS and its ability to read in Excel or Access data. Well, you learn something new every day.

A bigger screen?

A recent bit of thinking has caused me to cast my mind back over all the screens that have sat in front of me while working with computers over the years. Well, things have come a long way from the spare television that I used with a Commodore 64 that I occasionally got to exploring the thing. Needless to say, a variety of dedicated CRT screens ensued as I started to make use of Apple and IBM compatible PC’s provided in computing labs and other such places before I bought an example of the latter as my first ever PC of my own. That sported a 15″ display that stood out a little in times when 14″ ones were mainstream but a 17″ Iiyama followed it when its operational quality deteriorated. That Iiyama came south with me from Edinburgh as I moved to where the work was and offered sterling service before it too started to succumb to aging.

During the time that the Iiyama CRT screen was my mainstay at home, there were changes afoot in the world of computer displays. A weighty 21″ Philips screen was what greeted me on a first day at work but 21″ Eizo LCD displays were set to replace those behemoths and remain in use as if to prove the longevity of LCD panels and the validity of using what had been sufficient for laptops for a decade or so. In fact, the same comment regarding reliability applies to the screen that now is what I use at home, a 17″ Iiyama LCD panel (yes, I stuck with the same brand when I changed technologies longer ago than I like to remember).

However, that hasn’t stopped me wondering about my display needs and it’s screen size that is making me think rather than the reliability of the current panel. That is a reflection on how my home computing needs have changed over time and they show how my non-computing interests have evolved too. Photography is but one of these and the move the digital capture has brought with a greater deal of image processing, so much that I wonder if I need to make less photos rather than bringing home so many that it can be hard to pick out the ones that are deserving of a wider viewing. That is but one area where a bigger screen would help but there is another and it arises from my interest in exploring countryside on foot or on my bike: digital mapping. When planning outings, it would be nice to have a wider field of view to be able to see more at a larger scale.

None of the above is a showstopper that would be the case if the screen itself was unreliable so I am going to take my time on this one. The prospect of sharing desktops across two screens is another idea but that needs some thought about where it all would fit; the room that I have set aside for working at my computer isn’t the largest but it’ll need to do. After the space side of things, then there’s the matter of setting up the hardware. Quite how a dual display is going to work with a KVM setup is something to explore as is the adding of extra video cards to existing machines. After the hardware fiddling, the software side of things is not a concern that I have because of when I used laptop as my main machine for a while last year. That confirmed that Windows (Vista but it has been possible since 2000 anyway…) and Ubuntu (other modern Linux distributions should work too…) can cope with desktop sharing out of the box.

Apart from the nice thoughts of having more desktop space, the other tempting side to all of this is what you can get for not much outlay. It isn’t impossible to get a 22″ display for less than £200 and the prices for 24″ ones are tempting too. That’s a far cry from paying next to £300 (if my memory serves me correctly) for that 17″ Iiyama and I’d hope that the quality is as good as ever.

It’s all very well talking about pricing but you need to sit down and choose a make and model when you get to deciding on a purchase. There is plenty of choice so that would take a while but magazine reviews will come in handy here. Saying that, last year’s computing misadventures have me questioning the sense of going for what a magazine places on its A-list. They also have me minded to go to a nearby computer shop to make a purchase rather than choosing a supplier on the web; it is easier to take back a faulty unit if you don’t have far to go. Speaking of faulty units, last year has left me contemplating waiting until the year is older before making any acquisitions of computer kit. All of that has put the idea of buying a new screen on the low priority list, nice to have but not essential. For now, that is where it stays but you never know what the attractions of a shiny new thing can do…