Installing VirtualBox on Mint with a CentOS Guest

Christmas is almost upon us. Black Friday has been followed by Small Business Saturday and Cyber Monday.
The rest of the month obviously started on Skint Tuesday.
Fortunately for all us geeks, Santa Claus is real. He’s currently posing as Richard Stallman.
I mean, look at the facts. He’s got the beard, he likes to give stuff away for free, and he most definitely has a “naughty” list.

Thanks to Santa Stallman and others like him, I can amuse myself in the Holidays without putting any more strain on my Credit Card.

My main machine is currently running Mint 17 with the Cinnamon desktop. Whilst I’m very happy with this arrangement, I would like to play with other Operating Systems, but without all the hassle of installing/uninstalling etc.
Now, I do have Virtualbox on a Windows partition, but I would rather indulge my OS promiscuity from the comfort of Linux… sorry Santa – GNU/Linux.

So what I’m going to cover here is :

  • Installing VirtualBox on a Debian-based distro
  • Installing CentOS as a Guest Operating System
  • Installing VirtualBox Guest Additions Drivers on CentOS

Continue reading

Getting Python to play with Oracle using cxOracle on Mint and Ubuntu

“We need to go through Tow-ces-ter”, suggested Deb.
“It’s pronounced Toast-er”, I corrected gently.
“Well, that’s just silly”, came the indignant response, “I mean, why can’t they just spell it as it sounds ?”
At this point I resisted the temptation of pointing out that, in her Welsh homeland, placenames are, if anything, even more difficult to pronounce if you’ve only ever seen them written down.
Llanelli is a linguistic trap for the unwary let alone the intriguingly named Betws-Y-Coed.
Instead, I reflected on the fact that, even when you have directions, things can sometimes be a little less than straight forward.

Which brings me to the wonderful world of Python. Having spent some time playing around with this language, I wanted to see how easy it is to plug it into Oracle.
To do this, I needed the cxOracle Python library.
Unfortunately, installation of this library proved somewhat less than straightforward – on Linux Mint at least.
What follows are the gory details of how I got it working in the hope that it will help anyone else struggling with this particular conundurum. Continue reading

Installing SQLDeveloper 4 on Mint and Ubuntu – Minus the Alien

Deb recently bought a new kettle.
Now, a kettle used to simply boil water and turn itself off when it was done.
Not this thing.
It lights up as it boils and announces the fact that it’s finished with a melodious ping.
It’s got gauges and lights and switches.
I’ve decided that it’s probably a Dalek in disguise.
Like Daleks (or at least, the original Daleks), it can’t go up stairs – or if it can, it’s not advertising the fact.
Every morning, descending to the kitchen is filled with trepidation.
When will the Dalek tire of vaporizing innocent water molecules and move on to World Domination…

Doc-tor ! Doc-tor ! I feel like a ket-tle !

Doc-tor ! Doc-tor ! I feel like a ket-tle !

I wouldn’t be entirely surprised to find that, like most whizzy modern appliances, it runs on Java.
Which brings us, by a fairly circuitous route, to the topic at hand – SQLDeveloper.

Oracle’s latest incarnation of it’s IDE does indeed run on Java – the version 7 JDK to be precise.
In this post, I’ll go through the steps required on Mint to :

  • Install the Java 7 JDK
  • Install SQLDeveloper 4
  • Persuade SQLDeveloper 4 to play nicely with Java
  • Add SQLDeveloper to the Cinnamon Menu

The good news is that we can do all of this without the messy alien conversion of an rpm package to .deb format.

NOTE – I’ve followed these steps on Mint13, but they should be pretty much the same for any Debian Distro.
Anyway, without further ado…

Continue reading

Generating an md5sum on Oracle Database LOBs – or how to organise your Holiday Snaps

Following the trend in these straightened times, Deb and I decided to stay at home this year rather than going away on holiday.
I say “decided”, but this was really more due to the fact we were terribly grown up and bought a house last year.
As a result, the only recreation we could afford was a walk around the garden…whilst pushing a lawn-mower.
In an attempt to recall happier times, I’ve had a look back of some of the photos from our last proper holiday, in Canada.
As well as providing some happy memories, this also gives me the opportunity to explore how to compare an operating system file ( such as a jpeg) with a LOB held in the database.
Continue reading

Simple Pleasures…rlwrap and SQL*Plus Command Line editing on Linux

Fat, bald, likes a drink and a smoke. No, not me. That’s a description of Darren Lehman, the new coach of the Australian Cricket Team.
Sounds like a good bloke to me.
As a cricket fan, with the Ashes as the highlight of the sporting summer, I’m getting a horrible sense of deja vu.
If you read the press, Australian and English, you might be forgiven for thinking that the series is a foregone conclusion.
Yes, England should win, on paper. However, unless the groundsmen at the relevant venues have been doing something very innovative, the Tests themselves will be played on grass.
In order to take my mind off some of the more worrying parallels with this series and the one in 1989 – when Alan Border and a bunch of Aussie no-hopers demolished England 4-0 – I’ve been looking at one of those niggling little problems that I always mean to get sorted but never quite get round to.

Generally speaking, I much prefer Linux to Windows. There is however, on area where Windows has the upper hand.
When you’re working in SQL*Plus, Windows allows command line recall and editing by default. This feature is not present in Linux by default.
However, Linux, being Linux, there is a handy utility that can implement this functionality. It’s called rlwrap.
What I’m going to cover here is :

  • a recap of built-in SQL*Plus editing capabilities
  • Using rlwrap with SQL*Plus
  • The joys of TAB-Completion

Continue reading

Customising the Oracle XE Menu in XFCE – why it’s better to be vegetarian

Roberto Goldbrick. The name of the central character in a biting satire about a Premiership footballer ? Actually, it’s the name of the horse I drew out in the Office Grand National Sweep Stake.

“Oh well”, said Deb as the winner crossed the line with Roberto nowhere to be seen, “by next week it’ll be a value frozen lasagne”.
That’s the thing about vegetarians, they do like to assert their moral superiority at times. It can be quite difficult to find a suitable riposte. After all, you feel a bit of a twit accusing someone of vegicide.

In order to overcome my disappointment, I’ve taken refuge in Mint 14 XFCE running on my netbook.

Using the steps here and here I’ve managed to install Oracle 11gXE without any problems….apart from the fact that the Menu items now appear on the Others menu.
Being a lightweight desktop, XFCE doesn’t provide a default GUI to enable menu editing, so I’ve had to do a bit of investigation…
Continue reading

ORA-00845: MEMORY_TARGET error installing Oracle XE on Mint and Ubuntu

It was my turn to “cook” tonight. Deb was quite emphatic on that point. Continuing the fine and long-held tradition, sustained through generations of British manhood, I duly trudged down to the chippy.
Fish and chips, with that unique and exquisite smell of malt vinegar. Never mind all those fancy aftershaves, for us Brits it’s Sarsons…pour homme.
Except that, when I get to the shop, I find that I have no cash on me and they don’t accept cards.
No, not even “Chip and Pin”.
Eventually, the hunter gatherer returns ( having made a short detour to an ATM) to be greeted by the now ravenous family. Honestly, this cooking lark is all go.

It could be worse I suppose. I mean, the recipe for Victoria Sponge doesn’t suddenly stop working for no readily apparent reason, unlike, to take a random example, installing Oracle XE on Mint and Ubuntu.

When I wrote the original post, all was working perfectly. Mint 11, Oracle XE 11g, job done.
However, Mint 13 ( or Maya, if you prefer) is a bit of a different story. So, for that matter is Ubuntu 11.10 and above.

At this point, I’d like to say a big thanks to Gil Standen, whose comment on the original post was spot on in pin-pointing and solving this issue.

So, if you’ve found your way here having been frustrated in your installation attempts by this pesky error, what follows is an explanation of the issue, together with the steps that I used to resolve it on Mint 13. Continue reading