Forms of communication

Jun 26, 2014 / 0 comments

I am struck by the fragmentation in communication mechanisms. Let's look at how I have communicated with my friends in the past few days:

  • Phone call
    Tried and tested, though I tend to avoid them. I've made some deliberate calls to sort out immediate plans, and at least one accidental call caused by user error which resulted in talking to someone it was good to hear from.
  • Text message
    Again, reasonably tried and tested. I miss the inability to use Google Voice when I'm in the UK; I'd much rather read and compose text messages from my web browser when I'm near a computer than type them on my phone, even if it does have a keyboard.
  • Email
    One of my favourite methods of communication. Suitable for quick messages or longer screeds. I can throw links in and expect you to be able to click them. I can put lots of detail so that everything is covered easily. I can confuse you by quoting correctly. I guess while I do read email on my phone I'm less likely to reply there as I'm always a bit embarrassed how the clients cope with replies.
  • IRC
    Like, I suspect, many readers of my blog posts, I'm still a daily user of IRC. There are friends I keep in touch with mostly via this method. It's great. It's like Twitter for old people and much better in many ways.
  • Skype
    This started out as a work thing. It was the way in which the Belfast office communicated with the US, it become the way the Belfast office communicated with each other and when I moved on it was the way in which I kept in contact with a group of people I consider good friends. It's great for calls (I feel bad saying that, but it's an idea executed well across multiple platforms and any other VOIP stuff I've played with has been much more of a hassle), but the one to one and group chat functionality is pretty spot on as well. Also has the advantage that I can turn it off and mostly not end up with work queries.
  • Google Hangouts
    I actually quite like these. They work on my phone, I can poke them from a web browser, I can dump more than just text into them. IRC is better in some ways, but I do like the additional flexibility I get from a Hangout. It doesn't play well with people who haven't drunk the Google koolaid, which is the main reason I haven't managed to convince the Skype group chat group to move it over here.
  • Facebook messenger
    I hate this. On the face of it there's not a lot of difference between it and Hangouts, but the app wants more and more privileges, I'm less likely to be logged into Facebook (e.g. I avoid it at work, whereas there are good reasons I'd be logged into my Google account there, though less so since the demise of Reader) and I don't think it's as nicely implemented. However there are a few people who it's easiest to get hold of via this method. And there's a certain amount of mesmerisation by the floaty wee faces it invokes on my phone.

While some of these work better for me than others really what I'd like is to use fewer of them, and I can't see that happening any time soon. I don't want to have to run a handful of different messaging apps on my phone. I also don't want to be limited to only using my laptop or my phone for something - I'd much prefer to be able to pickup the phone, laptop or tablet depending on what I'm up to and have my full range of communication available. Some of these things can be aggregated together, but that will then lose some of the advantages. And I'm sure that even if I got rid of one or two of the above there'd be something to fill the gap along shortly (I have, for example, so far completely avoided WhatsApp).

Choosing a new laptop

Feb 11, 2014 / 0 comments

Recently I’ve been thinking about getting a new laptop. I have this rule that a laptop should last me at least 3 years (ideally more) and my old laptop was bought in September 2010. So for the past few months I’ve been trying to work out if there’s something suitable on the market that is a good replacement (last time I didn’t manage to find something that ticked all the boxes, but did pretty well for the price I paid).

To start with I decided to track my laptops over time - largely because one of my concerns was about the size of a replacement, because I have a significant leaning towards subnotebooks. In the end the reason I decided to upgrade was for some extra CPU grunt; my old machine had a tendency to get pretty hot under any sort of load.

DateModelCPUScreenRAMStorageW (mm)H (mm)D (mm)WeightCost
1991Amstrad PPC 640DNEC V30 8MHz9" 640x200 non-backlit green LCD640k2 x 3.5" FDD45023010010kg???
August 1997Compaq Aero 4/33c486sx337.8" 640x480 CSTN LCD4MB80MB260190431.6kg???
July 2002Compaq Evo N200P-III 700MHz10.4" 1024x768 TFT192MB20GB251198201.1kg£939.99
August 2005Toshiba Portege R200Pentium M 753 1.2GHz12.1" 1024x768 TFT1280MB60GB286229201.29kg£1313.58
September 2008Asus EEE 901Atom N270 1.6GHz8.9" 1024x600 TFT2GB4GB + 16GB SSD248175231.1kg£299.99
September 2010Acer Aspire 1830TCore-i5 470UM 1.33GHz11.6" 1366x768 TFT8GB500GB284203281.4kg$699.99 (~ £480)

The EEE didn’t actually replace the Toshiba, but I mention it for completeness. It was actually the only machine I moved to the US with, but after about a month of it as my primary machine I realized it wasn’t an option for day to day use - though it was fantastic as a machine to throw in an overnight bag, especially when coupled with a 3G dongle.

I wasn’t keen on significantly increasing the size of my laptop. There are a number of decent 13” Ultrabook options out there, and I looked at a few of them, but nothing grabbed me as being worth the increase in size. Also I wanted something better than the Acer - one of the major problems was finding something smaller than 13” that had 8G RAM, let alone more. There’s a significant trend towards everything soldered in for the smaller/slimmer notebooks, which makes some sense but means that the base spec had better be right.

Much to my surprise the Microsoft Surface Pro 2 looked like an option. It comes with an i5-4300U processor (at least since around Christmas 2013), and the 256/512G SSD models have 8G RAM. Screen resolution is an attractive true HD (1920x1080) and the 10” display means it’s smaller than the Aspire. Unfortunately the keyboard lets it down. It’s fine given a flat surface, but not great if you want to support the whole thing on your lap. Which is something I tend to do with my laptop, whether that’s on the sofa, or in bed, or on a bus/train.

Another option was the Sony Vaio Pro 11. This is a pretty sweet laptop (I managed to get to play with one at a Sony store in the US). Super slim and light. 8GB RAM. True HD screen. However I have bad memories of the build quality of the older Vaios and the fact that there was /no/ user replaceable parts put me off - it’s a safe bet that a laptop battery is going to need replaced in a 3 year lifespan.

What I managed to find, and purchase, was a Dell Latitude E7240. I admit that the Dell brand made me wary - while I’ve not had any issue with their desktops I didn’t associated their laptops as being particularly high quality. Mind you, I could say the same for Acer and I’ve been very pleased with the Aspire (if they’d had a more up to date model I’d have bought it). I bought the E7240 with the Core-i5 4300U (so the same as the Surface Pro 2) and True HD touch screen. It has a replaceable battery, expandable RAM (up to 16G) and the storage is an mSATA SSD. It also came with a built in 3G card. At 12.5” it’s a little bigger than my old machine, but I decided that was a reasonable idea given the higher resolution. I’m typing this article on it now, having finally completed the setup and migration of the data from the old laptop to it this evening. More details once I’ve been using it for a little bit I think.

Fixing my parents' ADSL

Jan 17, 2014 / 0 comments

I was back at my parents’ over Christmas, like usual. Before I got back my Dad had mentioned they’d been having ADSL stability issues. Previously I’d noticed some issues with keeping a connection up for more than a couple of days, but it had got so bad he was noticing problems during the day. The eventual resolution isn’t going to surprise anyone who’s dealt with these things before, but I went through a number of steps to try and improve things.

Firstly, I arranged for a new router to be delivered before I got back. My old Netgear DG834G was still in use and while it didn’t seem to have been the problem I’d been meaning to get something with 802.11n instead of the 802.11g it supports for a while. I ended up with a TP-Link TD-W8980, which has dual band wifi, ADSL2+, GigE switch and looked to have some basic OpenWRT support in case I want to play with that in the future. Switching over was relatively simple and as part of that procedure I also switched the ADSL microfilter in use (I’ve seen these fail before with no apparent cause).

Once the new router was up I looked at trying to get some line statistics from it. Unfortunately although it supports SNMP I found it didn’t provide the ADSL MIB, meaning I ended up doing some web scraping to get the upstream/downstream sync rates/SNR/attenuation details. Examination of these over the first day indicated an excessive amount of noise on the line. The ISP offer the ability in their web interface to change the target SNR for the line. I increased this from 6db to 9db in the hope of some extra stability. This resulted in a 2Mb/s drop in the sync speed for the line, but as this brought it down to 18Mb/s I wasn’t too worried about that.

Watching the stats for a further few days indicated that there were still regular periods of excessive noise, so I removed the faceplate from the NTE5 master BT socket, removing all extensions from the line. This resulted in regaining the 2Mb/s that had been lost from increasing the SNR target, and after watching the line for a few days confirmed that it had significantly decreased the noise levels. It turned out that the old external ringer that was already present on the line when my parents’ moved in was still connected, although it had stopped working some time previously. Also there was an unused and much spliced extension in place. Removed both of these and replacing the NTE5 faceplate led to a line that was still stable. At the time of writing the connection has been up since before the new year, significantly longer than it had managed for some time.

As I said at the start I doubt this comes as a surprise to anyone who’s dealt with this sort of line issue before. It wasn’t particularly surprising to me (other than the level of the noise present), but I went through each of the steps to try and be sure that I had isolated the root cause and could be sure things were actually better. It turned out that doing the screen scraping and graphing the results was a good way to verify this. Observe:

ADSL Noise Graph

The blue/red lines indicate the SNR for the upstream and downstream links - the initial lower area is when this was set to a 6db target, then later is a 9db target. Green are the forward error correction errors divided by 100 (to make everything fit better on the same graph). These are correctable, but still indicate issues. Yellow are CRC errors, indicating something that actually caused a problem. They can be clearly seen to correlate with the FEC errors, which makes sense. Notice the huge difference removing the extensions makes to both of these numbers. Also notice just how clear graphing the data makes things - it was easy to show my parents’ the graph and indicate how things had been improved and should thus be better.

Thoughts on SSDs and encryption

Dec 3, 2013 / 0 comments

My laptop is just over 3 years old, which is about the point I start to think about a replacement. At present there’s nothing that’s an obvious contender so I’ve been looking at an SSD to prolong it by another year or two.

One of the other thoughts I had is that I currently use dm-crypt under Linux to provide whole disk encryption for everything except the boot partition - I have a bunch of my personal financial and immigration documents stored that I’d prefer not to get disclosed if my laptop is stolen. Modern drives have started offered integral AES encryption options, so perhaps I could offload that to the drive (my i5 470UM lacks the hardware instructions for this).

General consensus in the pub (where all the best security advice is to be found) is that no one present trusted SSD firmware authors to not use some badly chosen AES crypto mode, or leave the key lying around plain text in easily readable flash, or some other implementation mishap.

So how hard would it be to retrofit reliable (or at least source verifiable and thus more reliable) crypto to an SSD? There was an impressive article recently about reverse engineering the firmware of a HDD, to the point of modifying data returned to the host and also running Linux on the controller. It seems that SSD firmware should be easier - NAND is simpler to talk to than motors and magnetic sensors, right? It’s a case of gluing together a SATA interface, a NAND controller and an AES offload engine, yes?

Aside from the minor matter of finding a suitable drive with an available JTAG interface, a controller with docs (or more likely that can be reverse engineered) and enough time to produce a replacement open firmware, that is.

Alternatively can anyone provide some idea of how secure the available laptop SSDs on the market actually are? I’m fine with “the NSA can read your data if they want” because a determined attacker will be able to find other ways to get my data anyway, but I don’t want “anyone who finds the drive can use this loophole in the firmware by wiggling some bits with jtag to dump the key and read all your data”.

Building a new house server

Apr 1, 2013 / 0 comments

I’ve moved (only a couple of blocks from where I was before), and as the new place has Webpass I’ve reluctantly given up my connection, along with its static IPv4 address and ISP IPv6 tunnel. Hard to resist a 200Mb/s ethernet connection for the same price I was paying for 18Mb/s ADSL2 though.

However that leaves my DGN3500 router somewhat inappropriate for providing my net connection. Freed from the need for an ADSL/cable router I decided it was time to build an all in one house server (I’m a believer in as few always on boxes as possible). I already had a nettop acting as a media box, but wanted to build something that would handle:

  • Gateway for the external network connection
    • Routing to internal ethernet
    • 2.4GHz wifi router
    • 5GHz wifi router
  • Printer server
  • House NAS
    • Backup server (syncing externally as well)
    • DLNA server
  • mpd server
  • ATSC based PVR

Probably in that order if it turns out I’m asking too much. The intention is the box is the only one that always needs to be on, so I wanted it to be low power consumption. I also wanted the option of hooking it up to the TV if it turned out to have enough grunt, so the case needed to be something suitable for the living room.

I like Intel’s approach to graphics drivers, in particular the existence of Free video acceleration support, so I went with an Intel Core i3-3220T as the processor. It’s a 35W Ivybridge processor with HD 2500 graphics, plus I got it for a decent price.

For the case I chose a CFI A2059. There’s a local supplier I was able to pick it up from, it has a couple of large fans which helps keeps the noise down while keeping things cool and as I was aiming for backup / file sharing being more important than a media box the 2 hot swap bays tipped the balance away from an AV style case.

The small case limits the motherboard options. I wanted twin GigE ports so the external was entirely separate from the internal (my switch does VLANs so I could have made do with a single port, but with a 200Mb/s connection I didn’t really want to share the port). The Gigabyte GA-H77N-WIFI seemed to fit the bill, with the added advantage of a built in WiFi card (an Intel 2230 in a mini PCI-E slot) which leaves the PCI-E slot free for either a TV tuner or a second WiFi card to cover 5GHz.

I maxed out the board with 2 8G G.SKILL DDR3-1600 DIMMs. I normally go Crucial because I’ve found them reliable, but these were slightly cheaper and available from the same place as the motherboard.

Finally I added a Seagate ST4000DM000 for storage. It actually came from a Backup Plus that Costco were selling for about $20 less than the bare drive sells for. The plan is to add at least another 1T drive to RAID1 the most important bits (or possibly a 2T - it depends which of my existing drives I can tidy stuff off most easily).

Of course it’s running Debian and I took the opportunity to try out the RC1 Wheezy image. For extra giggles I did an EFI install; this all worked fine except I didn’t end up with grub-efi installed at the end, instead I had grub-pc. I booted with legacy BIOS enabled and followed Tanguy’s switch to UEFI boot instructions.

Further notes on software setup to follow…

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