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Archive for 2010

26
Nov

USB console cable for Cisco Catalyst

Cisco’s new line of equipment now use a mini-USB cable for console configuration. There is no longer a need for a USB to serial adapter or a roll-over cable.

Connecting the USB cable on Linux should give you a new ACM device that looks something like this: “/dev/ttyACM0″.

To verify, you can also look through your dmesg or /var/log/messages :

[265430.720082] usb 4-1: new full speed USB device using uhci_hcd and address 4
[265430.914246] cdc_acm 4-1:1.0: This device cannot do calls on its own. It is not a modem.
[265430.914305] cdc_acm 4-1:1.0: ttyACM0: USB ACM device

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24
Nov

Ubuntu 10.10 Maverick with 2.6.37 kernel

If you want the latest (read bleeding edge) kernel that the Ubuntu developers are working, then have a look here:

Ubuntu Dev Kernels

Be sure to download the 3 files matching your architecture and install.

I am currently using 2.6.37-rc3-natty which will be the kernel that Natty Narwhal (11.04) will be based on. It just works, everything is detected and there is a noticeable increase in responsiveness.
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7
Oct

threading.Thread vs. multiprocessing.Process

The Feather or the Anvil?  


First a bit of background: I was tasked with created a high level tester for my company’s system. The idea is create 1 or more monkeys to pound away at the company’s product for a very long time. A concurrent parallel programming project with the requirement that it needed to be compatible with 2.6.2 version of Python.

With threading, you get real posix threads (pthread) which works pretty well. They implicitly share state with the parent thread and do not use IPC or messaging. They have low latency and low overall resource footprint.

However there are drawbacks that made further development using threads a real problem. that is the use of signals. Such as threads not handling signals, working with the global interpreter lock (GIL, only one thread allowed to run at a time), and more. Read moreRead more

30
Sep

xorg 1.9 versus fglrx

With the release of Ubuntu (Meerkat) 10.10 just 10 days away, the ubuntu x-swat people have been busy getting fglrx ready for release. The fglrx now compiles against latest Meerkat kernel and finally resolves the unknown symbol issue.

In the laptop is a ATI Mobility Radeon HD 3670 and with the latest fglrx driver usability is awful. There is horrible tearing when using “Appearance -> Visual Effects -> Normal”, which had to be set back to “None” just to be usable. Even on “None”, scrolling down in documents, chrome, firefox and Skype all give blurred or stuttered graphics.

These are for me “do not use” releases.
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23
Sep

Ubuntu 10.10 Maverick Meerkat on Dell Studio XPS 1640

After a brief time with Karmic (10.04), the laptop was upgraded to the beta of Maverick. Everything works out of the box with no additional tricks necessary in getting the Dell Studio XPS 1640 fully functional.

The only drawback I found in upgrading from Karmic was the loss of fglrx as a xorg-server driver. Maverick is shipping with the 1.9 version of xorg-server which is ABI incompatible with what fglrx is compiled against.

The exact error is:
undefined symbol: savedScreenInfo
which causes X not to start.

The rumour is that ATI will release a fglrx package that is compiled against 1.9 version of xorg-server when Maverick ships on Sunday, October 10th. Read moreRead more