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PySIG Notes, 26 April 2007

By Ted Roche on April 27, 2007 in Apple Macintosh OS X, Home Page, Linux, Microsoft, OpenSource, Python, Technology

Thirteen attendees made it to the April meeting of the Python Special Interest Group, held as usual at the Amoskeag Business Incubator, Commercial Street, Manchester, NH on the fourth Thursday of the month at 7 PM.

Bill Sconce lead off the meeting with a printed agenda and a round of introductions. Several new people were welcomed to the group; a range of levels of experience with computers and specifically Python made for a good mixed crowd.

Martin LeDoux showed off homemade bookbinding of the Python tutorial. Using an HP laser and Adobe Acrobat, Martin printed duplex 2-up folded, cut, glued and bound a pretty handy homemade book. Very cool.

Shawn K. O’Shea showed off the tarfile module which allows creation, querying, extraction and manipulation of tar files (with gz or bz2 compression) from within Python. This can be a real handy way to create cross-platform installable packages that would run on OS X, Linux or Windows.

Shawn also mentioned that there was a Google API for the Google Calendar with examples in Python scripting. Someone asked what that might be used for, and I offered the LUG coordinator Nag-O-Matic as a great example of using automation with calendars.

Bill attempted an introduction to Python datatypes by creating a hierarchy from primitive to complex objects. Kent had an objection to the terminology, and countered with chapter 3 of the _library_ reference (not chapter 3 of the Python reference which Bill was using) and a vigorous discussion ensued. That’s the point of the meeting, after all. And it’s far less likely to erupt into a flamewar in person. All sides had some good points, examples and counterexamples, and most of us learned more about Python internals. Good stuff.

Kent started Kent’s Korner 4: Iterators and Generators at 9 PM, when the milk and cookies were starting to kick in, The crowd was a bit more subdued, having spent their energy harassing Bill (and heckling Ben, in abstentia). Iterators went quite quickly. Generators woke the crowd up. Bill Sconce came up with a great example of greenbar color code generator, where the boss decides there should be two reds, three greens, alternating and repeating, though he may change his mind once he sees it. Off-script, Kent took off with this example, and followed it with a discussion of parameter passing to a generator.

Kent really has a gift for shedding light on these sometimes obuse topics; his examples really helped make the functionality clear, and working through the real-world example proposed at the meeting gave us all some idea of what was involved.

Kent also mentioned that he’s using IPython (note the capitalization; guess it’s not an Apple product!) an improved interactive shell.

Meeting called at 9:44. Wow. Long meeting, but a very productive one. One of the attendees wrote to me this morning that he went home and altered some of his scripts based on what he learned at the meeting. No greater praise could we ask for.

Thanks to Bill Sconce for running the meeting, the Amoskeag Business Incubator for the facilities, Alex Hewitt for wrestling with the network, to Martin, Shawn and Kent for presenting, and to all for attending and participating.

Next meeting May 24th, topic TBA.

Postscript: Like the previous meetings, we saw examples running in Python on OS X, Windows (VMWare on the Mac, I think) and Linux. It Just Works.

Notes from MerriLUG: Christoph Doerbeck: Xen on RHEL5

By Ted Roche on April 25, 2007 in Home Page, Linux, OpenSource, Technology

Thirty people attended the April meeting of the Merrimack Valley Linux
User Group, held as usual on the third Thursday of the month at Martha’s
Exchange in Nashua.

Heather did a fine job of welcoming the large crowd, listing some
upcoming events (remember, you can always find them on
http://www.gnhlug.org), and requesting feedback on next month’s topic: a
professional graphics designer has offered to discuss what’s available
in Linux for graphics, but wants feedback on what to focus on: removing
red eye from photographs, structured drawings, etc. Let Heather know
what you’re looking to do with graphics in Linux.

Christoph was the main presenter. He is a Sales Engineer with Red Hat
and has quite a history with Linux/UNIX. He arrived with three laptops
and his own gigabit network to demonstrate several configurations of
virtualization. One laptop lacked the new hardware support and was
relegated to running VMWare. The other two machines (an HP with an AMD
chip with the magick SVx bits, and a “StinkPad” – his term, not mine! –
with the Intel VTx/VTi capabilities) were capable of using Xen with full
or para-virtualization. Christoph demonstrated both, and used the three
machines to show how a virtual machine could be transferred from one
machine to the other. Suspending and moving the VM was not successful
(it’s a demo, these things never work), but the harder one, moving a
running session was successful, demonstrated vividly with a running
video on his controlling machine streamed from a server that started on
one machine and finished on the other. Bravo!

There was also a discussion of the other alternative for virtualization,
single-kernel-image virtualization, where multiple sessions are running
in multiple zones, somewhat like a “chroot jail.” Examples of this kind
of VM include Solaris Zones, Virtuozzo and Open VZ. Members of the
audience contributed insights to some of the other projects going on,
such as the KVM (Kernel Virtual Machine) project favored by some of the
kernel developers, UML (User Mode Linux) and others.

Christoph wrapped up with a long and thorough question-and-answer
session. He then offered a completely different topic: he mastered a DVD
with menus, music, video overlays completely in Linux and had some clips
to show off. A general consensus was that he was welcome to come back at
his convenience to talk about that, too!

Thanks to Christoph for the great demo, to Heather and Jim for
organizing the meeting, to the folks at Martha’s Exchange for providing
the facilities, and to all for attending and participating.

Thunderbird 2.0 email client goes gold

By Ted Roche on April 23, 2007 in Home Page, Linux, OpenSource, Technology

DesktopLinux.com relays the news that the Thunderbird 2.0 email client goes gold. ‘Way cool. Looking forward to trying this out. I’ve been using T-bird 1.x for quite some time now, and it’s moved to becoming my primary email client, edging out Safari on the Mac and Evolution on the Linux platform. Mozillazine points out more information, including release notes and feature lists. Now, this is a Two-Point-Oh release, and my advice to the conservatives would be to hold off for the Two-Point-Oh-One version, or at least until a patch or two comes out, if you’re not comfortable installing and uninstalling mail clients. Make a backup, of course. Note that Linux clients have a funky problem with spaces in the path, so avoid spaces.

MerriLUG, 19-April: Christoph Doerbeck, Xen on RHEL5

By Ted Roche on April 9, 2007 in Home Page, Linux, Technology

A not to be missed presentation: the Merrimack Valley Linux User Group will host Christoph Doerbeck of RedHat presenting “Virtualization on Linux,” a live demo of the Xen technology running on Red Hat Enterprise Linux 5. Details here. Reservations are strongly encouraged for dinner: we’ve had a couple of huge showings at MerriLUG lately, and the staff at Martha’s have been very accomodating at getting everyone fed and on time for the meeting. I suspect this one could be SRO also.

Notes from CentraLUG, 2-April-2007: Bill Stearns on LVM

By Ted Roche on April 3, 2007 in Home Page, Linux, OpenSource, Technology

A great meeting last night. The Central New Hampshire Linux User Group met at the usual place and time: The New Hampshire Technical Institute‘s Library, Room 146, 7PM on the first Monday.

I did my usual rounds of announcements, Shawn O’Shea pointed out that besides for the discuss and announce mailing lists, you can also subscribe to the lists via RSS by using one of GNHLUG’s archival sites. Add one of these to your favorite RSS readers to see the GNHLUG announcements: mail-archive.com or gmane.org

Everyone got to introduce themselves and speak a little bit about what they’re up to. I passed around a couple lists of topics and speakers from the wiki to find out what the attendees want to see for future sessions.

Bill Stearns presented “LVM: Logical Volume Management.” He explained about the basic need to expand or re-allocate disk resources without making hard partition changes, in some cases without even shutting down. We started right in on an exercise: using the loopback device and some spare space in /var/tmp, we created three loopback block devices. We assigned them as PVs (Physical Volumes) and allocated two to a Volume Group. Then, space could be allocated out of the volume group to provide the space needed. Additional PVs could be added to the VG, additional space from the VG could be allocated to a mount. We had a good discussion about the choice of filesystems and the different processing required for ext3, reiser, xfs, jfs file systems – most of which can be resized when on-line. (Bill recommended the MythTV HOWTO for a good discussion of which file system to use.

We had a good side conversation at this point about the mount tables and the significance of several flags Bill had. An intesnse discussion of ‘noatime’ – useful for hierarchical file management, but generally of little use, and a lot of disk activity, power consumption, speed decrease, and for FlashROM devicers, perhaps lifetime shortening can be avoided by adding noatime to the mount tab. Bill also had war stories about the security implications of nodev and nosuid both of which are a good idea for insertable media unless you have a specific reason for needing them.

We finished up the LVM exercise by adding the third PV to the VG and then resizing the ext3 partition to include the space. Bill took questions from the audience: one lady had just installed LVM on the Linux partition on her mainframe (!) that weekend, and wanted to know more about LVM striping. Other questions on reliability, use with RAID. Bill had some pointers for adding additional storage: use of USB2 (not USB1!) external drives (Bill hasn’t been happy with Firewire storage on Linux) or using an external storage solution (he mentioned CoRAID which uses rackable ethernet-to-ATA raw drives; Bill had one sample to play with) and handled some questions further afield, like the file defragmenter Bill has on his site.

Yet another great LUG meeting. Thanks to Bill Stearns for the great presentation (and 3-ring-bound handouts) and providing the raffle door prizes. Thanks to Bill Sconce for providing the projector and doing the note-taking during the meeting. Thanks to the New Hampshire Technical Institute for providing the facilities.

Look forward to a great presentation on OpenWRT by Ben Scott at the May 7th meeting (where you can expect him to be heckled) and another great presentation on Drupal by Seth Cohn on June 4th. Hope to see you there.

Life After VFP

By Ted Roche on April 2, 2007 in FoxPro, Home Page, LAMP, Linux, Microsoft, MySQL, OpenSource, Personal, PHP, Python, Technology

Robert Jennings posts Yet “Another Life After VFP Thread.” For those not following VFP closely, MS recently announced a confirmation of earlier news that there were no plans for a VFP version 10, and that the VFP scripts in the project known as Sedna would be released under some sort of public license. Poor communications lead to media and Slashdot reports that VFP was to be Open Sourced, sadly not the case.

Robert does a good job of outlining the huge cost in moving a vertical-niche application into another development environment, language and runtime. Most sophisticated specialty applications have person-years of investment built into them, knowledge not easily extracted, transferred or translated to any new environment. Regardless of whether that new environment is Dot Net, Dabo, LAMP, Python or Visual Fred, there will be a huge cost and risk with any enterprise making this switch.

Unlike the Open Source world, when a vendor choses to discontinue a product, developers have little choice but to move along. While many folks point out the upside that the product will likely run for years to come, and a lack of Microsoft official support doesn’t instantly obsolete a product (DOS apps can still be found, after all), there is an immediate slowdown in the custom software market, and a longer-term turning away from the product by customers. Large-scale vertical products have to be operating with 5- and 10-year plans for reinvestment and changes in direction, to ensure they can fund “The Next Big Thing” while continuing to deliver good value to their customers today and tomorrow.

This is not a death knell for the product. The writing has been on the wall for years. But developers with large applications have to be looking around for a new platform.

FoxPro developers always viewed themselves with a bit of “Battlestar Galactica” mythology: a rag-tag crew of self-taught developers from the PC Revolution, they survived the dBASE wars and the implosion of Ashton-Tate. Working under a cruel master who never promoted their product, they persevered. MS’ internal team developing VFP did amazing things on a shoestring budget, introducing a fairly smooth transition from procedural to object-oriented, from developer-guided to event-driven interfaces, from characters to pixels, from local ISAM to RDBMS. The VFP IDE was a remarkable environment in which to develop rich-client, component-based, web-driven or even server-based applications. I will miss it, and look forward to becoming as skilled at my next platform.

DLSLUG: April 5th: Todd Underwood: ZFS

By Ted Roche on March 30, 2007 in Home Page, Linux, OpenSource, Technology

Bill McGonigle announces the April meeting of the Dartmouth – Lake Sunapee Linux User Group. The main presentation will be “ZFS: The Last Word in Filesystems, ” presented by Todd Underwood, VP of Operations and Professional Services, Renesys Corporation. Here’s the pitch:

ZFS is the most original work in storage management in years. It offers a revolutionary, integrated approach to block device, raid, volume management and filesystem technology. We’ll take a high-level look at what makes ZFS so different from previous storage technologies and look at efforts to port ZFS to free operating systems (ZFS is available for FreeBSD and in a userland port to Linux, but the path will not be easy).

Todd has with more than 10 years experience in architecting, building, and supporting large-scale distributed systems. Before Renesys, Todd was senior vice president and chief technology officer at Oso Grande Technologies, the largest Internet service provider in New Mexico, where he was the lead consultant in the security practice. Before that, Todd was chief technology officer at Lightdart Managed Data Centers, a co-location and hosting start-up built in partnership with Public Service Company of New Mexico. As a graduate student, Todd led the effort studying high-speed networking for large-scale computer clusters at the University of New Mexico. Todd holds a B.A. from Columbia College, Columbia University and an M.S. in computer science from the University of New Mexico.

Looking forward to the meeting. Hope to see you there!

CentraLUG, 2 April 2007: Bill Stearns on Logical Volume Management

By Ted Roche on March 25, 2007 in Home Page, Linux, OpenSource, Technology

The monthly meeting of CentraLUG, the Concord/Central New Hampshire chapter of the Greater New Hampshire Linux Users Group, occurs on the first Monday of each month on the New Hampshire Institute Campus starting at 7 PM.

This month, we’ll be meeting in our usual location, Room 146 of the Library/Learning Center/Bookstore, http://www.nhti.net/nhtimap.pdf , marked as “I” on that map. Directions and maps are available on the NHTI site at http://www.nhti.edu and on the GNHLUG site at http://wiki.gnhlug.org/twiki2/bin/view/Www/DirectionsToCentraLUG. The
main meeting starts at 7 PM, with Bill Stearns presenting LVM: Logical Volume Management. Open to the public. Free admission. Tell your friends.

Bill is an authority in the field of security, an instructor for the SANS Institute and an activist in several anti-spam efforts. Visit
http://www.stearns,org for a list of some of the interesting projects he’s been working on and packages he maintains. At April’s meeting, Bill will explain the infrastructure of LVM and how to work with it. LVM is a great technology that allows you to add disk space to running systems, manage the mapping of logical and physical volumes and manipulate disk usage. With the correct choice of hardware and file systems, much of the work can be done while the systems continue to run! Bill has some practical insights into how these systems work, and can talk about some of the subtleties of why you might choose LVM-atop-RAID vs. RAID-atop-LVM. Attendees are encouraged to bring laptops: using temporary space (no need to repartition), Bill will use some loopback tricks to let you create some devices and manipulate the LVM commands – a great hands-on experience!

More details at about this meeting and the group are available at http://www.centralug.org and http://www.gnhlug.org as I learn them!

In future meetings, we are looking forward to Ben Scott demoing OpenWRT (May) and Seth Cohn showing off Drupal (June) – dates and times not yet confirmed and in flux, so stay tuned. Hope to see you there!

MonadLUG notes, 8-Mar-2007: tac and “Pitch Your Distro”

By Ted Roche on March 19, 2007 in Home Page, Linux, Technology

The second Thursday of the month is the usual meeting of the Monadnock Area Linux User Group, MonadLUG, at the SAU #1 offices on Hancock Road in Peterborough. This month, Ray Côté ran a discussion on “Pitch Your Distro” and Bill Sconce took on the “Man Page of the Month” on the command tac.

You won’t think you could make much of a presentation on tac, but that would be underestimating Bill Sconce 😉 Here’s the short form: tac is cat backwards. Longer form: tac lets concatenates files, but reverses the line ordering of the result, so you get last line first. There are only a couple switches, -s to specify a separator other than newline and -r to use a regex separator. Using this simple tool, Bill was able to present a wicked example that reversed not only line order by character order, and lead to a discussion about the use of regular expressions, piping, precedence, quoting and backticks. A good time was had by all.

The main discussion was a let’s-go-around-the-room discussion of what distros are in use and why and for what. With nine people present (and one of them a non-combatant), how many distros would you expect? We heard about: Debian, Slackware, OpenBSD, OS X, Fedora, RedHat, CentOS, SuSE, Mandrake, Ubuntu, Xubuntu, more RedHat, Knoppix, Gentoo, Libranet and some Knoppix war stories. Many aspects of the different distros were discussed: cost, support, lifespan, the difficulties of sound cards, and more.

Many thanks to Ray for running the meeting, Bill for tac and bringing a projector, and all for participating.

Next month’s meeting (April 12th) will have Seth Cohn presenting Drupal. Hope to see you there!

CentraLUG notes from Andy Bair’s Digital Forensic File Carving presentation

By Ted Roche on March 19, 2007 in Home Page, Linux, OpenSource, Security, Technology

Our thanks to Andy Bair for making the trip north from Massachusetts to present to the Central New Hampshire Linux User Group on March 5th, 2007, the first Monday of the month, at the New Hampshire Technical Institute’s Library. Andy announced that his work at MITRE was done and that he would be starting a job at Korelogic in the immediate future.

Andy worked with several friends at KoreLogic to take on the Digital Forensic Research Workshop (DFRWS) 2006 File Carving Challenge. They were supplied with a 50 megabyte “chunk” from a hard drive with the assignment to find as many files in that chunk as possible. The DFRWS’ motivation was to move the state of the art forward, and all participants were required to supply the source code of the applications they developed. Andy and his team won the challenge, beating out a number of other teams, notably Simson Garfinkel, who came in second. Andy demonstrated the procedures they worked out, talked about the algorithms they used, and showed the graphing of the results that made boundary detection and anomaly detection more easy to pick out. Andy and his team extended the UNIX magic technique to detect patterns in files, extending magic to XMagic which included regular expressions and more sophisticated rules to match files to the patterns. It was a very interesting presentation, presented well. Andy’s presentation, the source code and original data can be found at this link [Updated link – tr, 15-Feb-2010].

Thanks to Andy for the presentation, to Bill Sconce for supplying the projector, and to the New Hampshire Technical Institute for providing the facilities.

Upcoming presentations include:

Bill Stearns demonstrating Logical Volume Management April 2nd,
Seth Cohn presenting Drupal on May 7th, and
Ben Scott presenting OpenWRT on June 4th.

We plan to meet at the usual location, but keep an eye out for a more detailed announcement as the date gets closer.

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