BTest-2 Release Notes
This page contains hardware release notes for an early prototype of the XO-1 laptop.
The Meaning of BTest-2
There are typically one or two builds of systems internally before an external beta test. The BTest-2 build is earlier in the development cycle than systems are usually made available, and is correspondingly rougher. This is the beta test of completed electronics, as the Altera FPGA used for CaFE has been replaced by a functional ASIC. The camera, SD slot and NAND flash are interfaced via CaFE; the ASIC version is in BTest-2 and has significantly higher performance for both SD and NAND flash, and uses significantly less power.
The BTest-1 laptops were built with an extra 128 MByte of RAM, to partially make up for well known memory problems in key applications, in particular the web browser, based on Firefox's Gecko technology. Work is well underway to reduce the browser's footprint; some of this work is visible in Firefox 2.0 and is now in the latest Sugar builds (post build 239). BTest-2 was built with 128 MByte of RAM total; this is necessary so that we can qualify the multiple sources of RAM in working systems for high volume production. After a batch of B2s (B2-1) had been manufactured, it became clear that production systems were going to have 256 MByte of RAM, and another batch of BTest-2 laptops (B2-2) were manufactured with 256 MByte of RAM.
Note that we are also testing an alternate battery chemistry from NiMH; a lithium based battery chemistry has become available that has none of the safety or environmental problems of Lithium Ion, is less costly than NiMH (Nickel prices have gone through the roof in the last year), and can charge at much higher temperatures, important for use in some parts of the world which can be so hot as to exceed the temperature at which NiMH can be charged. These batteries can be identified by large labels "Battery Sample" on the battery packs.
The hardware specification is elsewhere in the wiki.
If for some reason you get bad data in the SPI boot FLASH so the system won't run the firmware, you can reload the SPI FLASH with a special cable.
Software Release Notes
There is a separate page for Software Release Notes. For an introduction to the machine's software, see the B1 Demo Notes page.
Library Release Notes
OLPC has started a Library of material. The Library Release Notes has release note information about the early content available.
Hardware Release Notes
Our master list of hardware and mechanical issues and status can be found in the trac system we use. Please check this list before entering new issues: but please do enter issues you discover. The items below are the most significant from the list.
- The keyboard may have problems due to a short cable
- the most irritating problem on BTest-2 is the fact that the keyboard may stop working properly, due to a cable 1mm too short and slightly too much insulation. Flexing the base of the system may pull the cable out of its connector. The field repair of reseating the connector (which requires disassembling the base assembly) is not all that difficult, but annoying.
- Power management is as yet unimplemented
- Therefore you cannot suspend and resume the machine (yet). The preparatory work in the firmware is complete, in development, the systems suspend and resume, but it is not yet ready to deploy. We have BTest-4 as a goal for working suspend/resume in the field.
- LiFe batteries incorrectly flash red light
- LiFe batteries are lighter and have "battery sample" on the back; if they flash the red "battery low" LED, removing and reinserting the battery will get the indicator back to correctness.
Fixed since BTest-1
- The battery charging algorithms have problems
- The old EC code shipped with some units had a bug which prevented startup with low battery and another bug which prevented charging with a low battery, and also high power usage by the EC, which would drain a battery if left unplugged in a matter of a day or two. Updating to firmware Q2B83 should fix most battery charging problems; please report any further difficulties. Please read this bug report for more information. BTest-2 should also be able to "resurrect" batteries that are so discharged that they cannot even be sensed when put into a system by a new trickle charger circuit. Unfortunately, there are a few batteries which cannot be recovered, due to flash memory in the battery being set to the wrong value, so the battery cannot talk to the laptop.
- Inconsistent battery charge state indications
- Fixed Q2B81 firmware. The EC can't report proper charging or capacity information and is overly conservative on the amount of power remaining, as the hardware chosen for the battery pack to report capacity is incorrect; this should be fixed in the BTest-3 build.
- Keyboard keys occasionally stop working, and sometimes the machine does not reboot.
- (ESD problem with the embedded controller.) This has not been seen on BTest-2 hardware. One of the most irritating and noticeable problems using BTest-1 systems is a static discharge problem that can lockup pins or entirely crash the embedded controller, causing some or all of the keyboard keys or touch pad to stop functioning (requiring removing the battery for a period to allow the EC to reset fully). We believe this has been fixed in BTest-2. We will therefore be very interested if anyone sees this problem in BTest-2.
- Internal Microphone
- The internal microphone is still mispositioned in BTest-2 (too close to the speaker), and build 239 does not have the codec properly configured to avoid feedback. One of the second source microphones is particularly bad. The BTest-3 hardware has the microphone on the other side of the screen.
- Touchpads are too "noisy"
- This is being mitigated with the addition of a Mylar sheet on top of each touchpad. The Mylar sheets improve touchpad performance for B-Test 1 machiness too. You can also recalibrate the touchpad, by touching all four corner keys at the same time (aka four finger salute), and should expect to need to when you change the laptop to and from power. The Mylar sheet looks like a plastic sheet -- you should not remove it, else touchpad accuracy will decrease. BTest-3 touchpads should be auto-recalibrating and have the sheet integrated.
- SD high-speed not working yet
- We now do support high-speed SD, but are not seeing very high transfer rates when in high-speed mode yet. Fixed in build 303.
- Hardware performance is not what it will be
- Fixed in the Q2B81 and later firmware. The B-Test systems run 33% slower when USB networking is in use -- the internal wireless device is connected over USB, so triggers this problem.
- The resistive sensor does not work
- (for use with a stylus for writing), due to a design flaw: This is fixed on BTest-2 systems.
- The arrow keys ("game keys") cannot be distinguished from the arrow keys on the keyboard
- This is fixed on BTest-2 systems.
- The screen is covered by a plastic film by mistake
- This was resolved in BTest-2, and a diffuser coating significantly improves the screen quality.
- Manufacturing data values are in the wrong order
- This is fixed in BTest-2 (and when BTest-1 systems' firmware is first upgraded).
Design Release Notes
The BTest-2 laptops do not have textured plastic: this is intended for future builds.
- Other design issues are also under investigation
- Note that design is always an over constrained problem: it is often not possible to get every thing you would like in a design, though you can usually get most or all of what you value most.