Tag: technology

Walking desk – improved

After 50 hours of walking at my desk, a few shortcomings compelled me to action. Most of the treadmill surface was under the desk and not available for walking, forcing a shortened stride. It was also unsuitable for jogging or running. We left the treadmill on sliders, so it could be slid out for running. The most annoying problem was not being able to use the controls while standing on the treadmill.

On Saturday I did a little measuring and planning, and then cut out a 11″ x 32″ rectangle for the treadmills console to protrude through. I positioned the cutout 8″ from the front of the desk, leaving exactly enough space behind the console for my iMac to perch on. Then I slid the desk over the control unit and moved the desk surface up.

After everything was in position, I found two problems. The iMac fit but there wasn’t enough space between its chin and the back of the treadmill console to tilt. The solution was cutting a 1.5″ x 14″ notch at the rear (the part I stand in front of) of the desk cutout. That allowed the treadmill to move forward 1.5″ and now I can tilt the iMac.

The other problem was the shelf. With the initial cut, it didn’t fit. Anywhere. After adding the notch and moving the treadmill forward, it was mountable as can be seen. The ideal mounting distance from the front edge of the desk to the cutout is 12.5″. Everything fits perfectly.

I have used this new configuration for 10 hours now. I would like a little more desk available for my forearms to rest on, and I need to raise the desk surface. When I last raised it, I forgot to factor in the incline of the treadmill. Without intent, I created an adjustable height walking desk!

panasonic, a friend to consumers

panasonic.com shopping cart error

Dear Panasonic,

Thank you for your consumer friendly web site. I was all ready to pull out my credit card and buy that camera. At the last minute, you intervened and saved me.

PS: Consider hiring someone to finish setting up your shopping cart. Making it work properly in standards compliant browsers would be welcome too.

Handy domestic app

A year or two ago, I found GroceryIQ, a nifty shopping list application for the iPhone. It has an enormous built in catalog of grocery items, as well as being able to add custom items and custom stores. So, I can walk into REI, and it’ll show just the items I’m looking for.

The only feature I’ve wished for that it doesn’t have was syncing the list on Jen’s iPhone with the list on mine. A few months back, I poked around and lo and behold, the feature had been added.

Words cannot scarcely describe how wonderful this feature is. Any time Jen adds an item to her list, I get a push messsage that notifies me. And vice versa. When I open the app, the item is in my list.

Because the database is so large, items normally have the brand, size, and quantity as well. So when I buy something, I know I’m getting exactly the right product and quantity.

ZFS is production ready

Background

In July of 2008, I was tasked with building a system to back up thousands of Linux based servers. Previous systems using Amanda and Bacula had failed, principally because they required a full time backup administrator to maintain. My job was to build a backup system that required very little maintenance, scaled well, and made restoring data straight forward and easy.

I initially deployed BackupPC which features data deduplication and would likely have reduced our storage needs by more than 60%. I deployed on two SuperMicro systems, each equipped with dual quad-core CPUs, 16GB RAM, and 24 one terabyte disks. I built out one system with OpenSolaris and the other with FreeBSD. After testing, we deployed both with FreeBSD.

BackupPC ended up being inadequate so I wrote my own backup system on top of rsnapshot. My backup system generates rsnapshot config files and then drives multiple concurrent rsnapshot processes on each of the backup servers, pumping data to the backup disks as fast as they’ll take it. I hacked up rsnapshot for better error handling and reporting. I log exactly how much data each remote system has, as well as how much is transferred during each backup.

About ZFS

The main reason we deployed on ZFS was file system compression. After testing several settings, I settled on compression=gzip. I noticed no difference in system performance between compression settings. The backup system has been in production since, with very little attention since deployment.

When initially deployed, each backup server required manual tweaks so that they would only crash once a day. The multiple concurrent rsync processes created a workload that stressed the ZFS memory pools. Working with the lead FreeBSD ZFS developer helped the situation and my systems only crashed once a week. When ZFS v13 was merged into FreeBSD 8-current, memory management improved and my systems only crashed once a month.

Even during the months of using ZFS with frequent crashes, I never lost any data. And there’s no need to fsck the disks after crashes. My confidence in ZFS grew enough that when I upsized the disks in my home file server, I switched from gmirror (tried and true) to ZFS mirrors. I back up my public server to my home file server and saw the same occasional rsync induced crashes. About the time FreeBSD released 8.0 beta releases, I updated and the crashes ceased. So I updated these backup servers and they too have been stable ever since.

I have added another server to the pool and currently store 58 terabytes of data and over a billion files. My compression ratio averages 2.25, more than doubling the effective capacity of the disks we purchased. After FreeBSD 8 was released, I upgraded all the backup servers and could scarcely be more pleased.

And then I learned that deduplication is coming to ZFS. I can’t wait to test it.

ssh bruteforce attacks become sophisticated

SSH scans and bruteforce attacks that have have been common since my first SSH enabled server was attacked in 1996. Back then, attacks were so rare that monitoring logins and manually adding attackers IPs to /etc/hosts.allow (TCP Wrapper) was sufficient to keep systems secure.

In the mid 2000’s, the rise of botnets resulted in distributed bruteforce attacks, in which dozens of IPs (bots) would attempt to bruteforce my SSH daemons. I wrote a shell script that collected the IPs and added them to the TCP Wrappers deny list. A while later, denyhosts, was released and I started using it instead of my shell script.

Since installing denyhosts, I only monitor logins and scan the nightly security reports. In the past few years, the frequency of attacks has slowly risen but occasionally there are significant changes in attack frequency and duration. The last significant escalation I can recall was in the months leading up to McColo being shut down. Immediately after their shutdown, I noticed a dramatic reduction in bruteforce SSH attacks.

It was during that time of increased activity that I wrote Sentry. Like my original shell script and denyhosts, it adds attacking IPs to the TCP Wrappers deny list. Sentry also adds their IPs to my PF firewall. Sentry worked much the same as denyhosts, except that when someone attacks one of my IPs, they got blacklisted on all of them. The number of attacks that made it into my security logs dropped accordingly.

Months later, after McColo was shut down, the distributed attacks all but ceased. Since then, attacks have remained sporadic, perhaps 10 a week. In the last couple weeks, the number of attacks spiked. I’m seeing dozens of new IPs getting blacklisted each day. Unlike previous attacks, the usernames the attackers are using are not being duplicated, which means the command & control network behind this latest round of attacks is more intelligent than most.

less paper, no regrets, part 3

To get a single document into Paperless while accomplishing the goals listed in part 2 requires several steps:

  1. Scan documents to PDF files
  2. Process PDFs through OCR engine
  3. Import  PDFs into Paperless.app

The ScanSnap comes with ScanSnap Manager. SSM allows you to create scan profiles, which specify scan quality, destination (file, OCR app, Paperless.app, etc), and simplex versus duplex (one or both sides of the paper). There are 4 quality choices: Normal (150dpi, 18ppm), Better (200dpi, 12ppm), Best (300dpi, 6ppm), and Excellent (600dpi, 0.6ppm). Excellent is very slow. I use it only for scanning photos.

I ran a few OCR tests to determine what settings would result in the highest degree of OCR accuracy. Adobe suggests scanning in Black & White at 300 or 600 dpi. The tips I found on Abbyy’s site suggested that the higher quality the scan, the better the results. After experimenting, I reached the following conclusions:

  • Acrobat Pro goes a good job on high quality text documents
  • Acrobat does a poor job on halftone text (i.e., receipts printed on thermal printers, dot-matrix, faded documents)
  • On documents that Acrobat does poorly at, it does no better if the document is scanned in B&W versus color.
  • When scanning in B&W, faded receipts are often illegible. Scan in color instead.
  • Abbyy FineReader does a great job on most any legible scans
  • The difference between 600dpi and 300dpi is not significant

Factor in that disk is cheap, my time is not, and I’ll never be able to scan these documents again, and the settings I use for all documents is: Best, Duplex, and Color. Color is easy to desaturate to greyscale, the ScanSnap will omit the back side of the page if blank, and I can downsample images later if I need to. With Best quality, it takes about the same amount of time to scan a stack of documents as it takes me to sort, organize, and jog a fresh stack for the document feeder.

ScanSnap Manager will feed new scans directly to an application. So, I tested by configuring it to scan the document directly to FineReader for OCR processing. While that may work well for day-to-day SOHO needs, it is too slow when staring down a mountain of papers. For that, raw speed is required and nothing will get you through step 1 faster than saving to files.

There is one more setting to deal with. This dialog box describes the choice:

If I have a stack of 50 sheets in the document feeder, do I want them to end up as 50 PDF files, or one PDF with 50 pages?  If the 50 pages are each individual receipts, then I want them each as individual files. When I have more than one page in a document, such as a phone bill or American Express cardholder statements, a multipage PDF is perfect. The ScanSnap can’t really know my intent so I must tell it. I do so by creating two profiles, one called ‘Standard’ which is a multipage PDF. It takes everything I drop in the hopper and outputs a single PDF. My second profile is named ‘One file per page,’ and it does just that.

Next time, “the shortest path between 8 file drawers of paper and 10,000 PDFs”

less paper, and no regrets, part 1

Last year, our office bought a document scanner. Unlike every other scanner I had purchased or used, this thing was tiny. Its footprint on a desk is smaller than a piece of paper. It is designed specifically for turning pieces of paper into PDF documents. I had to try it. It scanned both sides of my paper in 3 seconds. One pass, both sides!

Such a gadget is very exciting because I have a lot of paper. I’m not a compulsive hoarder, but I do keep financial records longer than the minimum 7 years. Combine that with the documents retention required for our business and before long we had two 4-drawer file cabinets of documents. And a couple desk drawers. And the pile on Jen’s desk. And the pile in my hutch.

The prospect of making all that paper disappear helped me get over the resistance I had to parting with $400. So I purchased the SnapScan S510M (since replaced by the S1500M). While waiting for it to arrive, I started thinking about how I was going to organize the thousands of PDF files that would soon be residing on my hard drive.

I had nightmares of the days before iTunes when I had to painstakingly tag all my music by hand, and then organize the music files into directories so I had a slight chance of finding what I was looking for. I needed an iTunes equivalent for PDF documents. Google led me to ReceiptWallet, which has since become Mariner Paperless. It promised to be iTunes for documents, so I bought it. Instantly.

The SnapScan comes with several software packages: Adobe Acrobat Pro 8, CardIris, Abbyy FineReader OCR, and the SnapScan drivers.  With a large bucket of tools in place, it was time to do some planning.

To be continued…

My favorite iPhone/iTouch Apps

Grocery IQ ($0.99) – shopping lists

– organizes by store & aisle, includes a large DB of items, and you can email the list to your SO if they’re going to be stopping by the store. My only wish for this app is that it would sync shopping lists between phones.

The Weather Channel (free) – An excellent weather app, with hourly, 36 hour, and 10 day forecasts, doppler radar, etc.

AIM ($2.99) – Instant Messages with push

– Instead of IMs being sent via SMS to my phone while I’m ‘mobile’, they are sent via push (which is completely free).  If you want a multi-protocol client, have a look at beejive ($9.95). I prefer being ‘offline’ from my other IM accounts (jabber, MSN, facebook, etc) when I’m away from my computer.

Facebook (free)

– if you use facebook, this app is a must have. Upload photos and status updates from your phone. This app provides a second reason to have your phone in your hands while sitting with Uncle John. The first being, keeping your phone as far from the bowl as possible. 😉

Remote (free) – remote control for iTunes and Apple TV.

PasswordWallet – sync your PW  between your mac and iPhone. I find this app is essential since I use one time passwords everywhere. I wouldn’t be able to use many iPhone apps without this one.

WordPress (free) – write blog posts and upload photos.

Amazon.com (free) – Use it to check prices while at the store. Place orders. Buy stuff. Because it’s an app, it loads pages and performs searches faster than using amazon.com in Safari. It’s fast enough that it’s actually useful while you’re at the store. Or just buying something that you remembered while lying in bed.

E*Trade Mobile Pro (free) – useful app if you have an E*Trade account.

Skype (free) – Place skype calls via WiFi.

Motion-X ($3) – a full featured GPS application.

– Uses the iPhone build-in GPS and compass for navigation. Caches map data, which is extremely useful. I’ve taken tracks while out fishing and also used it while geocaching. Just make sure to have a spare battery pack available.

Lose It (free) –  weight loss app

– set some weight goals (mine is lose 1 lb per week). Each day, enter the food you eat and any exercise you do. Step onto the scales and record your weight. Makes calorie counting fast and fun.

TextFree ($6) – free unlimited SMS messages on iPhone and iPod Touch

Trapster (free) – Get alerts sent to your phone as you approach speed traps, red light cameras, and live police patrols.

iDisk (free) – Access to your .mac iDisk. Another handy way to get files to/from your iPhone.

Air Sharing ($5) – Launch this app and you can mount your iPhone on your Mac or PC as a remote disk (webdav). Drag and drop files to it.

Wikipanion (free) – Wikipedia interface. Faster than using Safari.