Two new tools..well old ones. Revamped Wednesday, 10 August 2011  
"top" is a great tool - very old. And lacking in many ways, 20+years after it first appeared.

"proc" is my version of top. I wrote it many many years ago for Solaris, so it could do what *I* wanted. I've had this tool for a long time. I ported it to Linux, and have been happy with it.

Why is it better? Because it does color. It crams more data into the screen real estate. It uses a better sorting algorithm (there are lots to choose from), and highlights memory deltas.

"proc" is available from my tools area (next door to dtrace).

Why am I bothering to talk about proc?

Because I realised as CPUs get faster, and with 8 cores on an i7, drilling down and understanding whats going on in a system requires more esoteric tools.

So, whats wrong with "proc"? For one thing, its easy to see something on screen which is of interest, but, on the next screen update, it might have disappeared. This can be annoying - as machines get bigger, more processes running, the screen real estate cannot show everything at once. Sometimes you want to go *backwards* and rewind what you just saw.

Well, that requires a bit of re-engineering. But its done. By default you can cycle back upto 20 mins of history. History is stored in /tmp/proc; by the time we factor in the process table, the amount of data is quite staggering (about 1GB of data per hour). This includes the key process attributes, along with extensions for /proc/pid/wchan, /proc/pid/stack etc. (Nearly everything is kept, but not absolutely everything; e.g. signal masks are not stored). And this includes the threads.

We also keep /proc/meminfo, /proc/vmstat and many more.

Theres so much data, that actually visually monitoring it is quite difficult. Just staring at /proc/meminfo has so many fields, one cannot understand/comprehend what is happening from one second to the next.

Even with history, its not comprehendable.

So, the second major update to "proc" is graphics. The ability to see, in graphical format, what is happening to the various key stats is very educational and illuminating.

The implementation of graphs is interesting. Rather than creating an X11 application or KDE or GNOME, I decided to implement this inside the terminal emulator. "fcterm" is my emulator of choice - and fcterm was recently enhanced to support various escape sequences to do line and rectangle drawing. By using simple printf/escape-sequences, anything can be drawn - sufficient for drawing graphs.

[I have a sampler in the fcterm/ctw distribution, available on my site, written in Perl, to show just about every /proc entry as a graph. Its crude, but effective, but quickly shows that dumping all graphs onto a page just overwhelms; that is why proc was enhanced].

I have just uploaded proc-b21, for you to play with (but you must use it inside fcterm; I havent validated what it does in another xterm). It is still a work in progress, so dont bother reporting bugs to me yet.

I will upload a few images in the next blog post.

Posted at 22:06:16 by fox | Permalink
  Virginmedia Tivo Saturday, 06 August 2011  
Sometimes, I dont understand the web. If you read the reviews of Virginmedias Tivo product, they all rave about how good it is.

But it isnt. The interface is buggy and designed by people who havent tried to read the text from across a living room, even on a big screen.

The fact that you cannot archive programs from the device without watching the same program on the main TV is, well, somewhat myopic.

The ethernet and USB interfaces do nothing (as yet). Why? Its 2011. (I think I know why, because the film industry doesnt want people to watch films away from a DRM controlled environment).

The on-demand and catch-up services are badly thought out and confusing.

The remote control is as bad as all other remote controls - it cannot be held in the hand and used in a one-handed mode - not if you are fast forwarding.

The fast forward on tivo is very badly thought out and confusing. Its idea of fast forward is 2x or 3x. One cannot quickly scroll through without a lot of button pressing. (The jump in 10min intervals is broken and confusing).

The suggestions do not understand recording and watching something - it only seems to work based on thumbs up/down.

Tivo does not understand a family who have different tastes and preferences.

The YouTube app is a joke. Watching 240x320 youtube videos in degraded quality on a 40" TV is about as ugly as you can get.

The above is typical of the glowing self-satisfying reports on the product. Multi-room streaming? How will that work? If that means I can watch tivo on my PC in another room, then I am salivating.

If it means I can watch one tivo from another room, then think on! Who is going to have two Tivos in a household?

Applications on the tivo are just a real joke. On the ipad, applications are great because it allows a degree of 'context' without having everything coming through the browser.

BTW the virgin Android TV guide app is poor. Very poor. It is welcomed - it is better than nothing, but it is one of those 'why am I wasting storage space on my device' apps. (You can control your tivo device from this app, to do remote recordings; but theres a serious glitch in the way it works - you cannot record a program if it is on in less than 35mins from now. Why?)

The tivo is 'not bad' but its certainly not a step up from the prior Virgin+ device.

Posted at 22:10:55 by fox | Permalink