modified: Saturday 27 February 2016
State of my ARM Chromebook
Since December 2013 I have been the proud owner of a Samsung series 2 Chromebook (aka 'snow chromebook'). Chrome OS provides little more than a web-browser, so I have been running Arch Linux ARM on it for most of this time.
This hardware does not use an x86 processor. This is the reason I chose it (along with it being cheap).
I thought it might be interesting to share the current condition of the hardware and software on my laptop. Some of the tweaks and tools I have made might interest other snow users. If you are embarrassed by how beat up your laptop looks, the pictures here might give you some relief.
|Processor||armv7h dual-core Samsung Exynos 5250 (I have a copy if link breaks)|
|Permanent storage||~16GB flash + some eeprom for bootloader, probably some on-processor flash too|
|Temporary storage||~2GB RAM|
|Screen||1366×768@60 LED backlit LCD, low quality (lots of bad angles)|
|Connectors||SD card slot, 1xUSB 2.0, 1xUSB 3.0, HDMI, 3.5mm TRS headphone output|
|Charger||12V, tiny unusual barrel connector|
|Battery||30Wh claimed two-cell LiPo|
I did not buy a model with the optional 3G modem.
In its natural habitat:
The silver-painted plastic case is marked, cracked and damaged all over. It has survived many drops and falls. The electronics have survived water spills. The corners are somewhat missing.
This laptop used to get carried directly in my bag along with books and my lunch.
You can see quite a bit of paint polishing on the keys and palm-rests. This is a problem that many laptops suffer over time. I do not suggest you try and clean away polished areas by scraping away the upper layer of paint -- you will get what has happened to my left palm rest.
The keyboard quality on the snow is not too bad, especially compared to my last laptop. None of the keys have broken and they do not feel flimsy. I much prefer keys with raised shapes on them however. Similarly the touchpad is much better than my last laptop (no phantom key presses!) but I still yearn for the joystick/red nipple style mouse inputs that are only really found on Lenovo (shudder!) Thinkpads these days.
The words of one of my friends: "your laptop is missing some battle armour". A long piece of plastic used to cover up the rear join, however it was prone to snagging on clothing and sheets. Over time pieces of it snapped off and it became more difficult to put back on.
Sadly the corner damage has caused some loss of functionality. The headphone jack no longer works:
There also used to be a hinged cover on the SD card slot, but that was also long ago snagged on something and lost. Too many parts of the case are easy to accidentally remove.
The insides of the laptop highlight how unique the design is:
The whole motherboard -- including the permanent storage, wifi and charge control circuitry -- is the blue PCB at the top-right of this picture. These size savings have been mandatory in the mobile phone and tablet markets, so it should not be surprising that the ARM-Soc based motherboard is this small. The CPU heatsink in some laptops is larger than the whole motherboard of this one.
The power consumption of this device is very low, so no fan or finned heatsink is necessary. A copper plate and heatpipe bridge most of the larger components and hangs out over the area where you can imagine the optional 3G module would sit.
A screw is intentionally missing from the top-left of the motherboard. This screw (and a little metal sticker that normally sits beneath it) are designed to short two PCB tracks together, telling the processor to keep the bootloader write-protected. I have since modified the bootloader.
Sidenote: there are several stages of bootloader on this device, all of which are confusing.
The big black thing is the battery. Two LiPo cells (and probably some protection/monitoring circtry between them, I have not had a look). These now only charge to about 75% of original capacity.
I stuck my uni timetable to the top of the laptop about a year ago to protect it from scratches. The bottom has not fared as well, espeically since the feet stopped sticking and I lost them:
Repairs and maintenance
I'm currently on my second screen. The first was lost to a plastic Chinese take-away container.
Stress damage is currently visible on the (new) screen as a few small areas of above-normal brightness. The same problem appeared with the previous screen and the body/lid is quite flexible.
It's important to keep debris clear of the plastic strip between the touchpad and the keyboard. This area contacts the screen and rubs against it during transport, leaving a rectangular section of the screen potmarked and dulled.
Small pieces of metal work their way through the plastic speaker grilles and stick around the edges of the speaker diaphragm. Often the speakers sound like they are clipping -- this is due to the debris. I have found that a strong magnet is the most effective way of removing the debris.
The rest of this blog post continues in dedicated page I have setup.
Soon I will release halinit, the init system I wrote to replace systemd on my snow. I'm waiting to see if another author minds some of their code being included. Apart from that, I have the whole article ready (with installation instructions) and the code neatified for release.
For everyone else that runs something other than chromeos on their snow: please share your experiences and stories.