Friday, 22 March 2013
Windows 7 filesharing limit
I have a Sonos music system at home, and it's great -- I use it to make music stored on my Windows 7 Media Center system accessible throughout the house, among other things.
One of the nice things about Sonos is that it's really easy to setup. I just point its music library at a network Share on my Media Center system and it automatically keeps everything indexed and up to date. Every now and again, however, I go to play a music track and I'm told it can't find it. Specifically, it can't access the file using the network share path, even though the file is there and I can play it fine locally on Media Center.
Recently, I finally figured out what was going on - a simple but not-very-well-publicised limitation built into Windows 7 Home Premium which restricts the resources used to manage network file shares. If you have a number of PCs in your house, as I do, all accessing shares on a particular PC, you can run out of resources. When this happens, any further attempts to access the share will fail. Not good!
Happily, there is a straightforward fix - Alan Lamielle describes it on his blog.
The short version is to find this registry key on the Windows 7 machine:
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache
and change the following registry key from '1' to ’3′:
Then restart the 'Server' service (or restart Windows itself if you prefer) and everything will be back to normal again.
Since making this change, I haven't had a single recurrance of the problem - happy days!
Wednesday, 13 February 2013
Fixing Visual Studio 2010 keyboard text selection
Short version: does shift-selecting blocks of text in Visual Studio, Word, Outlook, Notepad or other Windows apps mysteriously cancel your selection from time to time? The problem may be to do with your keyboard's PS2 to USB adapter. Skip to the end for an easy fix.
I spend a lot of time editing text. Sometimes, this is in Word or Vim, but mostly it's in Visual Studio's code editor. So, when something I'm used to breaks, something I do so often that it's hard-wired into my fingers, it gets my attention.
I often select blocks of text by holding down Shift, holding Cursor Down until the block of text has been selected, and then pressing Cursor Up to move back up a line or two. When I'm working quickly, I often press Cursor Up before releasing Cursor Down. And until recently, this would work perfectly - the Cursor Up stroke would take precedence over the repeating Cursor Down and things would smoothly come to a halt.
I started a new project recently which needed Visual Studio 2010 (I'd been using VS2008 until then). I installed VS2010 on a fresh development PC and pretty quickly noticed that whenever I tried to select a block of text, it would end up unselected again. Selecting it a second time, more carefully, worked fine. During periods of heavy editing, I might do this operation several times a minute, so this was DEEPLY AGGRAVATING.
I figured out that things worked fine as long as I released Cursor Down before pressing Cursor Up while making the selection. Unfortunately, training my fingers to do this was a lot harder than I expected, so the problem continued. Since I was only working on the VS2010 PC a couple of days a week, I was able to live with it. I checked Google, of course, but nobody else seemed to be suffering from this problem. I even used the Spy++ development tool to monitor keyboard messages going to the Visual Studio window, but nothing seemed amiss.
Over Christmas, I rebuilt my home office, incorporating some new monitors, KVMs, moving things around, etc. Soon after, I noticed the problem had spread to my main development PC. Worse, it turned out that applications other than Visual Studio were now being affected. Even Visual Studio 2008, which had been fine up until now, was suffering, as was Notepad, Outlook, and pretty much any application that accepted multi-line text input!
What was going on here? I checked a couple of my other PCs -- some of them were doing it, some of them not. Was this some sort of strange new virus with an unanticipated side-effect? Several full virus checks (all clean) suggested not. Both Windows 7 and Windows 8 systems were showing the problem, but I had other similar systems that were clear, as was Windows 2012. More intriguingly, when I connected to an afflicted system using remote desktop, the problem vanished. I even considered the issue might be related to a keyboard switch I was using to share a single keyboard & mouse between several PCs, but where I had such a setup, some of the PCs on the switch were fine, others were not.
At this point, I reckoned the cause must be some system utility I had installed on some but not all of the PCs, or possibly a Windows update. An audit of all such software didn't point to any culprits, however. And the problem continued to sit there, annoying the heck out of me on a daily basis.
Until finally, today, a break-through! I decided to connect an old PS/2 keyboard to my main PC at the same time as the USB KVM switch I was using day-to-day -- and using the old keyboard, the problem didn't occur! I then connected the PS/2 keyboard to a USB port, using a cheap PS2 to USB adapter, and the problem returned. It was something to do with the KVM after all.
The next step was to go back to Spy++ again and do some A/B comparisons. I used Notepad as my test application -- it's so simple that I figured there would be very little noise to get in the way. (I briefly had no output from Spy++, until I realised it could only monitor 32-bit applications on my Win7/64 PC; I fixed this by copying the 32-bit version of Notepad.exe across from a Win7 x86 system and monitoring that.)
Here's the pertinent output, showing the key sequence SHIFT, Down (held down to repeat several times), Up, release Down, release Up.
First, with the keyboard connected via USB:
P WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 Code:2A fExtended:0 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 Code:2A fExtended:0 fAltDown:0 fRepeat:1 fUp:0 P WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 Code:2A fExtended:0 fAltDown:0 fRepeat:1 fUp:0 P WM_KEYDOWN nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYUP nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:1 fUp:1 P WM_KEYDOWN nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYUP nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:1 fUp:1 P WM_KEYDOWN nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYUP nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:1 fUp:1 P WM_KEYDOWN nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYUP nVirtKey:VK_SHIFT cRepeat:1 Code:2A fExtended:0 fAltDown:0 fRepeat:1 fUp:1 P WM_KEYDOWN nVirtKey:VK_UP cRepeat:1 Code:48 fExtended:1 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYUP nVirtKey:VK_UP cRepeat:1 Code:48 fExtended:1 fAltDown:0 fRepeat:1 fUp:1 P WM_KEYUP nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:1 fUp:1
Now the same sequence, using the PS/2 keyboard connected directly to the PS/2 port:
P WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 Code:2A fExtended:0 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 Code:2A fExtended:0 fAltDown:0 fRepeat:1 fUp:0 P WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 Code:2A fExtended:0 fAltDown:0 fRepeat:1 fUp:0 P WM_KEYDOWN nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYDOWN nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:1 fUp:0 P WM_KEYDOWN nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:1 fUp:0 P WM_KEYDOWN nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:1 fUp:0 P WM_KEYDOWN nVirtKey:VK_UP cRepeat:1 Code:48 fExtended:1 fAltDown:0 fRepeat:0 fUp:0 P WM_KEYUP nVirtKey:VK_UP cRepeat:1 Code:48 fExtended:1 fAltDown:0 fRepeat:1 fUp:1 P WM_KEYUP nVirtKey:VK_DOWN cRepeat:1 Code:50 fExtended:1 fAltDown:0 fRepeat:1 fUp:1 P WM_KEYUP nVirtKey:VK_SHIFT cRepeat:1 Code:2A fExtended:0 fAltDown:0 fRepeat:1 fUp:1
There are two significant differences: the USB input seems to repeat keys by continually releasing and re-generating the keystroke (even though I had the Down key held down continually); more significantly, it generates an up-stroke for the Shift key as soon as I press Cursor Up (or indeed any other key, I discovered), before generating the Up keystroke -- essentially, the keyboard was not supporting N-key-rollover when connected via USB.
This second point is what was causing the problem, since if you select a block of text using Shift and then press Up on its own, it does indeed cancel the selection.
Okay, so now we have the cause - how to fix it? I knew from previous testing that a genuine USB keyboard didn't seem to exhibit this problem, so it must be something to do with my PS2 to USB adapter (actually, two different types, both with the same problem). I speculated that it might have something to do with the keyboard repeat speed -- perhaps Windows was simulating repeated keys in the USB driver if it thought the attached keyboard couldn't handle this itself, or perhaps the PS/2 keyboard's repeated codes were being remapped by the USB converter cable.
Next stop was to Control Panel -> Keyboard -> Speed where I tried setting the keyboard repeat speed to both its slowest and fastest setting. Amazingly, either setting fixed the problem completely! It seems that all you need to do is set the repeat speed to something other than the default; this magically makes things start behaving properly.
To confirm, I repeated my test with Spy++ and sure enough, the USB-connected keyboard is now correctly sending repeated KEY_DOWN codes and no longer sending a KEY_UP for Shift in advance of the Up keystroke being pressed. My guess is that this is a quirk of the built-in Windows USB keyboard driver, rather than something in the device itself, since identical behaviour occurred with two separate PS2 to USB converters.
So problem solved: I had adjusted the keyboard speed setting on some of my PCs, but not on others which is why the problem appeared to be so random.
Monday, 17 December 2012
Syncing sent mail between iPhone and Outlook
I use Outlook 2003 for most of my mail. However, since buying an iPhone last year, I've gradually been replying to more and more messages by phone. The convenience of being able to send a quick reply Right Now is great; it's one less email to deal with when I get back to my desk, and a good use of what would otherwise be dead time.
This creates a problem though: I use POP3 mail with Outlook so it doesn't see messages sent from my iPhone. If I want to check back on a reply weeks or months later, it can be difficult to locate.
To fix this, I have my iPhone configured to automatically BCC me on any messages or replies I send. This works but the BCC'd messages arrive in my Inbox as new messages which I then need to consciously ignore. They're also more difficult to find later on since I need to search my entire Inbox instead of just checking my Sent Items.
Today, I finally implemented a really simple, obvious solution I should have come up with months ago: using Outlook's Rules to automatically move such messages to the Sent Items folder. The trick is to use an obscure Rules feature that lets you check for specific keywords in the message header.
If you open any message sent from the iPhone in Outlook, and choose View Menu -> Options, you will see the full mail header. iPhone messages always have an X-Mailer header line reading "iPhone Mail (xxxx)". Outlook can use this to identify iPhone messages automatically and move them to Sent Items.
I don't want to move messages I receive from other iPhone users though, just messages sent from my iPhone. I also don't want to move messages sent to me - I often send myself iPhone messages to remind me to do things, or to quickly move photos from my phone to my desktop without having to sync. Outlook can handle both of these conditions by simply checking the To: and From: fields of the message.
Putting it altogether, I created a new Outlook Rule like this. (The steps are for Outlook 2003, but Outlook 2007/2010 should be similar):
- Select Rules and Alerts on the Outlook Tools menu
- Click to create a New Rule; start from a Blank rule, not a pre-defined template
- Turn on these conditions: From people or distribution list, and With specific words in the message header
- In the rule description below, edit the People or distribution list to include the address(es) you send iPhone mail from. Also edit the Specific words list to include the phrase iPhone Mail.
- Click Next and choose the actions Move it to a specific folder and optionally Flag it with a colored flag. (I move messages to my Sent Items folder, and flag them green to make them stand out, but you could create a folder specifically for iPhone messages if you prefer.)
- Click Next, then choose Except if sent only to me from the list of exceptions. This ensures that messages I forward to myself don't get moved to Sent Items.
- Click Next once more to finish creating the rule, give it a sensible rule name (I used iPhone Messages) and then, if you like, run it immediately on the contents of your Inbox. This tidied up all the existing messages I've sent from my iPhone over the past year.
Only takes a minute to set up, and now my Inbox feels like it's back under control again. Better, I can now easily find messages I sent on my iPhone while searching on my desktop.
(Yes, switching from POP3 to IMAP would let me do all this seamlessly, in principle, but there's something about the simplicity of POP3 that I continue to like.)
Tuesday, 20 November 2012
Monitoring network downtime with PRTG
I've been using MRTG for a while to monitor assorted servers, routers, and switches I manage at The Windmill. It's free, works pretty well, and is quite configurable. The graphs it produces are plain but functional, and they do the job.
Recently, I needed a tool to monitor my home network, primarily because the Cisco 3925 router provided by my Internet supplier, UPC, has had a nasty tendency to lockup every week or so. Now, UPC's 120 Mb/s Internet service is fantastic value, and performs exceptionally well, but having it randomly interrupted like this is really, really annoying -- especially when the router is buried in a small cupboard at the back of our attic, where all the TV wiring is concentrated.
I also have a wireless access point (an old reconditioned Eircom Netopia 2247) which periodically hangs, though on a different schedule to the Cisco. So, I figured it was time to start monitoring both devices to see exactly when they go offline, in the hope that I might be able to correlate it with other network activity.
While MRTG can do this, it's not the most user friendly of systems to configure. Since I crave nothing more than an easy life, I decided to look around for alternatives.
This brought me to PRTG, a commercial monitoring tool from Paessler that covers some of the same ground. It's free for up to 10 monitoring points, runs under Windows, and has a nice web-based GUI that makes it easy to configure or review logs from anywhere on my LAN. So, I decided to give it a try.
I've been using PRTG for about two months now, and it's working very well. There are a huge number of built-in sensors: everything from basic PING tests, SNMP polling of routers & switches to Windows system metrics (for any machine on the LAN) to remote website HTTP monitoring. With the 10 free sensors included in the evaluation copy, I was able to add rules for three websites I manage, my Wifi and Internet routers, a separate VPN router I use to access client networks, and also a few of my local machines:
PRTG lets you create sensor dependency trees: for example, I monitor the uptime of this website (www.snoopdos.com) but the monitoring rule says not to try and monitor it if the UPC Cisco router is down, OR if Google's main DNS server at 184.108.40.206 can't be reached. This ensures I don't get an onslaught of website failures in the log just because my Internet connection was interrupted.
PRTG also lets you raise alerts whenever a sensor goes on or offline, or crosses a threshold. For example, if the disk space on C:\ on my main Media Center TV system drops below 1 GB, I can easily have PRTG alert me, either by email or SMS.
I've barely scratched the surface of what's possible so far, but it's a very capable system. When Paessler emailed me today with an offer to upgrade my free 10-sensor license to 30 sensors in return for some blog coverage, it wasn't a difficult decision. While I only blog about products I actually like and use, PRTG now falls squarely into that camp. Give it a try and see what you think for yourself.
Monday, 5 December 2011
Why choose Snoopdos?
Like most engineers, technology is my comfort zone. It's easy to forget that running a successful business needs a sprinkling of sales & marketing, and even (gasp) self-promotion. So for a change, I thought I'd talk a little about Snoopdos itself and why you might want to consider us for your next project.
There are many reasons for choosing Snoopdos. Our team of experts combines highly communicative people with varied skills in a wide range of sectors which means we have a wealth of knowledge and creativity to offer you. We have collaborated internationally with great success. Our scope spans all kinds of projects for companies of all sizes. We can devise a program with which to achieve your goals. Take your business to the next level with our help!
We offer indepth consultancy services. Typically, we first evaluate your current set up. We do a general evaluation and quickly pinpoint what needs to change and how exactly to do so. We consider what positive ideas are already in place and design ways to make them even more powerful. There is no set program, since all companies differ, so we customize everything down to the details.
Whether you are an artistic start-up company or a big telecommunications operation, whether you have the most basic of sites or a large powerful one like O2 we can show you how to get more out of your online presence.
Don't underestimate the power of an effective website. An excellent website will not only provide great promotion and attract more clients to your services and products; done right, it can also open another stream of income for you as you select appropriate advertisements and links to display. Take your company international with the reach of an amazing site. We can get you there!
One of our core skills is software development. If your website or indeed other project requires bespoke development, we can deliver. Our team is extremely professional, able to work to deadlines and your specific requirements.
Please fell free to contact us at your earliest convenience so that we can schedule an initial meeting. We can discuss your needs and together decide on the best plan of action. We look forward to helping you accomplish your professional goals. Thank you for considering Snoopdos!
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