Micks' Musings

Now for a topic with a possible audience of zero (which is probably the number - besides spambots - who read this blog!). Over the last few weeks I have been investigating the performance of our application on z/OS. The application is written in C and runs in batch and CICS. A customer reported that our latest version was not performing as well as the version they were currently running. Testing showed there was a difference. The same tests did not show a difference on other platforms. z/OS has unique characteristics, not surprising given the hardware it runs on, and there are bound to be factors that affect performance that do not affect other platforms. We build our application using unix system services and link the final modules into a Dataset (load library). What this means is that we can use standard unix shell utilities, make files and other tools just like on any other unix platform. This makes development much easier. The final link is the first time anything leaves the unix e...

My phone thinks it is daylight saving time already! There is no way to tell it it isn't! To be fair it is only the clock / weather widget on my Android phone and all the other places that show the time have it right.

My old phone (as of about three weeks ago) was a windows mobile 6.5 handset and it got about 1 days from its battery. Then I dropped it on to a hard stone floor (is there such a thing as a soft stone floor?) and it started to misbehave. The sound would turn off, including the sound of the person talking to me! No ringtone or any other sound until I rebooted it. Then it was okay for a day or two but then it would not answer calls for two days until I rebooted it again. So I restored it from the custom ROM back to the manufacturers version of Windows mobile and installed Android (as an executable that was run after booting Windows mobile!). Now the battery life was less than a day! So I got a new (Huawei Sonic) phone for less than half what the old phone cost. A very nice, android based, phone. Then I got a $2 prepaid SIM for the old phone. Recharged it, activated the SIM and called the old phone. It answered! Since then it has sat on my desk for 9 days - the battery life is down t...

I have two linux file servers and they were both on fedora 14. I decided to upgrade them to fedora 15 and started using the two online upgrade methods - preupgrade and the Fedora documented way using yum. Both upgrades worked flawlessly but on one of the file servers it failed all the drives in the RAID6 array**. I restored from backup to fedora 14 and the RAID was fine and has stayed fine for a week since. Besides that problem I found the biggest problem with Fedora 15 is Gnome V3. It would only work in fallback mode on one system due to the PCI video card and on the other system it was really bad using VNC - the screen would not refresh - and I had to enable the fallback mode. For a system that is going to be used remotely Gnome 3 is useless - perhaps using X it may be better but with VNC it is hopeless. So I had mixed success with the upgrade - one is working fine on Fedora 15 and the other system is back at Fedora 14. ** a friend hates it when anyone says RAID array. Redundant Arra...

As luck (or Murphys Law) would have it as soon as I started writing about setting up my new file server it crashed and would no longer boot! It started getting kernel panics and other errors and I have tracked it down to careless application of Linux system updates and NOT rebooting immediately after applying them. The result was a non-booting system which would not even boot from an older kernel (accessed by using grub). So I had to reinstall Fedora 14. I did run memtest to check for memory problems and I swapped out the PCI-Express Video card for a PCI card so I also installed another PCE-Express RAID card to give the system the full 24 SATA ports. Everything was fine with the hardware checks.

After less than two years my media server was no longer able to be expanded. There was no more room to add disks and it had heating issues - it couldn't be kept cool enough. So it was time to plan the replacement. Based on what I have learnt from the build and operation of the first one I came up with a short list. 1. Must be able to be significantly expanded with more disks 2. Must have good cooling 3. It will run a recent linux 4. Because of the number of disks it will use RAID6 These criteria should help to address some of the shortcomings of the first file server. With RAID5 it was always a significant worry when a disk failed as the rebuild phase was a prime candidate to have another disk failure. With RAID6 there is the still a risk of a disk failure during the rebuild phase but it is reduced as there are two parity disks. Also if you have to wait for a new disk to arrive the RAID6 still has one parity disk left. To get good cooling and room for lots of disks meant researchin...

After my adventures with VNC my son has followed it up by getting his Steam account hijacked after unknowingly installing a key logger. Valve make it too easy by allowing the hijacker to change the email address without confirmation. You do get an email with a link but the link does not disable the change of email it merely directs you to a page where you can report the hijacking. Two days later and Valve have still not responded to the report. My son is still locked out of his Steam account and cannot play $500 worth of games he legally owns. Wake up Valve - do you want your games pirated? This was another lesson in computer security and highlights the ineffectiveness of the Steam system to deal with hijacking. At least there was no credit card information to get but it is frustrating how long Valve is taking to do anything about it. I do not know what the hijacker gets out of this - they cannot (I hope) transfer the games or gift the games to someone else and even if they did surely ...

My new linux box got hacked yesterday. I was careless. My ADSL router has upnp support and it is turned on by default. I enabled "Remote Desktop" in Linux - which is a version of vnc - and decided not to set a password as it would not be accessible from outside the local network. That was my first mistake. Last night I noticed a second connection to the linux box. Someone was using the browser and had connected to Western Union and was trying to install the flash plugin. They had not got very far as Fedora 14 does not install Flash on a 64bit system as it is still in beta so the install is not straightforward. I was able to disconnect this errant person before they got any further and I then disconnected the ADSL line from the modem to prevent another attempt and proceeded to diagnose what had happened. I checked the preferences for VNC and noticed the automatically configure the network check box had been selected and that it was reporting an external address could be ...

I have had a SmartQ V7 (7 inch Android tablet) for a while now and it has served me well. I have read a few books, browsed the web and played a few simplae games on it. However the one thing I found lacking was the screen was too small to read comics comfortably. So I have bought an ePad V2 10.2in Android tablet - with 512M of memory it had double the memory of the SmartQ V7 which is an improvement. Its screen is 1024x600 compared to 800x480. I have tested comic reading and it does fine. The extra size makes a world of difference. It doesn't fit in a (big) pocket like the SmartQ does but it is thinner and only slightly heavier so goes in my backpack comfortably. At the same time as getting the ePad I bought my wife an iPad. Similar size screen - wider but shorter (1024x768, 4x3 aspect ratio as compared to the 16x9 of the ePad) - but a much better screen with much better responsiveness. The iPad responds to screen touches much better than the ePad and is an overall much better table...

This is a cautionary tale with, hopefully, a happy ending. The other day a friends laptop failed to boot after installing some updates. Not an unusual tale but, due to failing to spot the clues, we ran the restore of the boot drive using the system restore partition. Unfortunately this wiped out the data that was there. The clue I should have spotted? The fact that it was trying to boot from the D: drive. Somehow the 100MB boot partition had been marked as active and had moved the C: drive to D: causing the boot failure. Now that the data we thought was safe on the D: drive was gone how could we get it back? The non-existent backup did not help so I turned to NTFS recovery software. The first application turned out to be a dud - it ran for 36 hours before I gave up on it. In the end I used a program called ZAR 9. It was able to scan the disk and present a list of restorable files in under an hour. Not all the files are good - reformatting and dumping a system image will cause some dama...