Latest revision as of 15:41, 12 December 2009

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This page is monitored by the OLPC team.

Note: If you are looking for a Hardware Recommendation for School Server, see XS_Recommended_Hardware. This page discusses a custom hardware platform created by OLPC for the School Server role.

Introduction

(As of mid-2008, the plans discussed here are on hold.)

In the medium-term we expect to provide a number of School server hardware platforms. OLPC, in order to support the deployment of laptops, especially in environmentally hostile or off-the-grid locations, is designing a reference platform in collaboration with our manufacturing partner, Quanta.

Planned platforms include:

XSX - A medium-term prototype, using OTS parts
An XO laptop - Equipped with an external disk drive, a laptop should be capable of performing as a school server for small (less than thirty laptop) schools.
XS - An environmentally rugged, very low power school server for up to 150 students. Should be available in November.

XS Specifications

This is a School server hardware platform designed with low power consumption and operation in environmentally challenging conditions as goals.

Processor

This hardware platform may be based on any processor architecture supported by the mainstream Linux kernel and libc software trees. We encourage the use of processors supported by Fedora Core 7.

Processor performance is difficult to characterize with a single number. We are looking for between 1200 and 1600 MIPs, capable of 120K+ interrupts/sec, with at least 1 GB/sec of memory throughput. At least 256KB of L2 cache should be provided.

For the XS Server, the processor is a PowerPC, the MPC7447A from Freescale, with AltiVec support. Apple calls it a G4.

Network Interfaces

The following are the integrated networking interfaces on XS. Additional interfaces may be added to the system using the peripheral interfaces.

Peripheral Interfaces

The following peripheral interfaces are provided for expanding the capabilities of the school server.

USB 2.0

At least six Universal Serial Bus (USB) 2.0 interfaces should be provided for extending the storage and communication capabilities of a School server.

This assumes that up to three external ports will be used for Active Antenna, another for an external CD/DVD RW, another for a possible WAN connection, and one last one for temporary USB key or external USB drive attachment.

The total amount of power consumed by the USB devices will be clamped to 2.5 A at 5 Volts (12.5 W) total, aggregrated across all devices. Any single device may pull up to 1.5 A (7.5 W).

PCI-Express Slot

A short, full height PCI-Express (4 channel) expansion slot is provided internally in the XS. This slot is intended for the addition of a DVB-S receiver and demodulator, but may be used for other purposes as well.

The power consumption of this expansion slot limited to 15 W. Exceeding this will lower the maximum ambient operating temperature of the server, and may also prevent the use of a second disk drive.

Non-Volatile Storage

to consider : how many drives are recommended for backups and replacement? with only 1 drive, what is the path to recovering a dead/dying drive? this may depend on quality of connection between server and upstream backup at a regional center

Internal Disk Drive

One internal 3.5 in. disk drive will be provided. The disk interface will be SATA (version 1 or 2). The capacity of this disk drive WILL vary, with a minimum size of 300 GB at this time.

A second 3.5 in. disk drive will be supported in the XS, primarily for onsite drive replacement, but also allowing storage expansion. Use of a second disk drive will significantly increase the power consumption of the server.

A fan-less aluminum disk drive cooler may be worthwhile as a prevention of overheating measure.

External Disk Drives

Additional disks may be added using the external USB 2.0 ports.

Flash

A fair amount (512 MB) of NAND Flash (solid state non-volatile) memory will be provided on the XS server to allow the operating system and minimal services to continue operation even though the primary disk drive has failed.

A smaller amount (512KB) of NOR Flash will be provided for storage of configuration information and boot firmware.

On OTS systems Flash storage is currently not needed - or used. If you can obtain flash disks for all your OTS XS machines, do discuss it in the mailing list - it is an extremely valuable addition.we are considering using adding USB keys or SD cards to allow similar functionality.

Power

The power specifications of the School server are important. Many schools do not have adequate, or regular, power. While the power consumption should be minimized (30W is a good target), consideration should be given to an integral (or optional modular) uninterruptible power supply (UPS). This is nothing more than a larger version of the laptop power supply!

In some test schools with minimal power, we are already deploying multiple (gang) battery chargers with integral UPS.

Possible methods of obtaining power are summarized in Battery_and_power.

Environmental

Temperature

The school server should meet the same environmental specifications for temperature as the laptop. This is 50 C ambient.

Water, Dust, and Salt Fog

The server should be resistant to water spray from all directions, but does not have to survive immersion. It should be capable of long-term operation in a constantly humid (100%) environment, with salt fog and dust.

While the server will contain fans, they will externally accessible for easy replacement and under software control to conserve power.

Connectors and buttons should be resistant to water and dust intrusion. Buttons should be sealed against water, and connectors located and cables dressed to prevent water intrusion.

Mounting

While the school server should be designed to sit on a flat surface, it should probably also be mountable (hangable) from a wall or post.

This shouldn't cause a problem unless the server includes batteries for a optional/modular UPS...

Drop and Shake

The school server should meet higher drop and shake specifications than standard consumer desktop PCs, to account for rough transport in the delivery.

@@ Line 1: / Line 1: @@
+{{translations}}
 {{OLPC}}
 [[Category:SchoolServer]]
+'''Note: If you are looking for a Hardware Recommendation for School Server, see [[XS_Recommended_Hardware]]. This page discusses a custom hardware platform created by OLPC for the School Server role.'''
-This is a description of the first dedicated hardware implementation of the [[School server]].
-An overview of the services provided by the [[School server]] is provided by the [[XS_Server_Services|Server Services]] document, with an accompanying [[XS_Server_Discussion|discussion of desired services]].  Also available is a [[XS_Server_Software|description of the first software implementation]].
 =Introduction=
+(As of mid-2008, the plans discussed here are on hold.)
-Unlike the current laptop, there will be a number of [[School server]] hardware platforms.  OLPC, in order to support the deployment of laptops, especially in environmentally hostile or off-the-grid locations, is designing a reference platform in collaboration with our manufacturing partner, Quanta.  We are also supporting efforts by candidate countries (such as Brazil) to manufacture a school server platform locally.
+In the medium-term we expect to provide a number of [[School server]] hardware platforms.  OLPC, in order to support the deployment of laptops, especially in environmentally hostile or off-the-grid locations, is designing a reference platform in collaboration with our manufacturing partner, Quanta.
-Current platforms include:
-* XSX - A short-term prototype, available now using OTS parts
+Planned platforms include:
+* [[XSX Server Implementation|XSX]] - A medium-term prototype, using OTS parts
 * An XO laptop - Equipped with an external disk drive, a laptop should be capable of performing as a school server for small (less than thirty laptop) schools.
 * XS - An environmentally rugged, very low power school server for up to 150 students.  Should be available in November.
@@ Line 28: / Line 30: @@
 ==Network Interfaces==
 The following are the integrated networking interfaces on XS.  Additional interfaces may be added to the system using the [[#Peripheral_Interfaces|peripheral interfaces]].
-===Wireless Mesh===
-The School server will have two or three [[Active Antenna]], an 802.11b/g [http://en.wikipedia.org/wiki/Wi-Fi WiFi] wireless mesh networking interface.  Each one of these serves as a mesh portal point operating on one of the three non-overlapping 802.11b channels (1, 6, and 11).
-While connected to the school servers using detachable five meter USB cables, the Active Antennas are considered integrated as there must always be at least one of these connected for proper server operation.  In the future, higher numbers (four or five) of more advanced (directional) Active Antennas may be used.
-These are not integrated physically into the XS school server. This allows them to be located optimally for RF transmission/reception, while the server is in a more accessible location.   It also allows for greater separation of the three antennas, operating simultaneously at neighboring frequencies.
-===Wired Networking===
-Providing at least two [http://en.wikipedia.org/wiki/100baseT wired ethernet] interfaces allows for reliable, high-bandwidth connection between a [[school server]] and its internet connection (if through a [http://en.wikipedia.org/wiki/DSL DSL] or [http://en.wikipedia.org/wiki/Satellite_modem satellite modem]), other school servers, and any non-laptop computer equipment.
-The current plan for XS is to provide two [http://en.wikipedia.org/wiki/1000baseT 1000baseT] ports and four [http://en.wikipedia.org/wiki/100baseT 100baseT] ports on the server.  The two high speed ports allow multiple servers in a school to form a high speed backbone, and the four additional ports on each server provide school network expansion without using external switches.  External switches are not encouraged, due to unknown quality and the requirement of external power.
-Each port will be provided with two LEDs indicating link status, simplifying network debugging.
 ==Peripheral Interfaces==
@@ Line 59: / Line 47: @@
 ==Non-Volatile Storage==
+''to consider : how many drives are recommended for backups and replacement? with only 1 drive, what is the path to recovering a dead/dying drive?  this may depend on quality of connection between server and upstream backup at a regional center''
 ===Internal Disk Drive===
@@ Line 66: / Line 55: @@
 A fan-less aluminum disk drive cooler may be worthwhile as a prevention of overheating measure.
-{{cleanup}}
-Network Attached storage off-site may be a good choice concerning  prevention of theft and natural disaster destruction, war conflict, etc.
-My Book™ World Edition™
-WDG1NC10000
-Network Storage System with
-Remote Access
-TB, Ethernet
-Access your data anywhere, anytime, even when your local computer is off.
-http://www.google.com/search?num=100&hl=en&safe=off&client=firefox-a&rls=com.google%3Aen-US%3Aofficial&hs=uoe&q=hard+drive+cooling+fanless&btnG=Search
-Some specific options and Manufacturers with their features & proprietary technologies: Shock resistance; error correction; prevention; electricity energy efficiency; encryption & security; etc.
-Western Digital:
-http://www.westerndigital.com/en/products/productcatalog.asp?language=en
-GreenPower™ Hard Drives GP drives from WD yield average drive power savings of 4-5 watts over competitors' drives while maintaining solid performance.
-http://www.westerndigital.com/en/products/greenpower/index.asp
-http://www.westerndigital.com/en/products/greenpower/family.asp?language=en
-WD RE2-GP WD5000ABPS
-SATA Hard Drives
-GB, 16 MB Cache, Power-saving
-RAID-specific time-limited error recovery (TLER) - Pioneered by WD, this feature prevents drive fallout caused by the extended hard drive error-recovery processes common to desktop drives.
-http://www.westerndigital.com/en/products/products.asp?driveid=386&language=en
-WD Caviar® GP WD5000AACS
-SATA Hard Drives
-GB, SATA 3 Gb/s
-Key Features
-Reduced power consumption - WD has reduced power consumption by up to 40 percent compared to competitors’ drives with the combination of WD's IntelliSeek™, IntelliPark™, and IntelliPower™ technologies.
-http://www.seagate.com/ww/v/index.jsp?locale=en-US&name=System_Builders&vgnextoid=ef39b2d54b1fd010VgnVCM100000dd04090aRCRD
-Barracuda ES.2 SATA 3.0-Gb/s 500-GB Hard Drive
-http://www.seagate.com/ww/v/index.jsp?vgnextoid=8c045cf536b43110VgnVCM100000f5ee0a0aRCRD&locale=en-US
-ST3500320NS
-The Barracuda® ES2 drive is perfect for high-capacity, 7200-RPM nearline storage where dollars/GB and watts/GB are primary metrics. It offers energy-saving PowerTrim™ features, internal data integrity protection, superior rotational vibration tolerance and a SATA 3.0-Gb/s interface.
-Momentus® Hard Drives
-http://www.seagate.com/www/en-us/products/laptops/momentus/
-Seagate® Momentus® hard drives provide the optimum combination of performance, capacity and mobility in a 2.5-inch form factor. They are also a good fit in certain non-PC applications, including external storage, copiers/printers and entry-level blade servers.
-Momentus 5400 PSD Laptop Hybrid Drives
-The Seagate® Momentus® 5400 PSD Hybrid Drive combines a hard drive and flash memory into a single device. Duplicating the most commonly used hard drive data onto the non-volatile cache for instant access provides faster boot-up and performance.
 ===External Disk Drives===
@@ Line 143: / Line 66: @@
 A smaller amount (512KB) of NOR Flash will be provided for storage of configuration information and boot firmware.
-On OTS systems, we are considering using adding USB keys or SD cards to allow similar functionality.
+On OTS systems Flash storage is currently not needed - or used. If you can obtain flash disks for all your OTS XS machines, do discuss it in the mailing list - it is an extremely valuable addition.we are considering using adding USB keys or SD cards to allow similar functionality.
 ==Power==
@@ Line 153: / Line 76: @@
 Possible methods of obtaining power are summarized in [[Battery_and_power]].
-http://www.powersupplies.net/default.asp
-NASA obviously could be a way to not "reinvent the wheel":
- K and M Electronics Power Supply Aboard NASA Spacecraft
-Power Supply for Miniature Quadrupole Mass Spectrometer
-This lightweight, low-power system is designed to operate unattended for a long time. http://www.techbriefs.com/index.php?option=com_staticxt&staticfile=Briefs/June00/NPO20493.html
-Useful article: http://www.motherboards.org/articles/guides/1487_1.html
-Possible vendor for a Fan-less redundant power -supply linked to an external daisy-chain expandable battery backup.
-Eventually servers could be integrated into a vehicle which would have obvious advantages: power source, clutch or gas pedal brake pedal anti theft device; evacuation in case a natural disaster warning is received.
-http://www.torchcomputers.co.uk/index.php?cPath=75
-MTV Think initiative
-http://think.mtv.com/Issues/environment
-their international affiliates with MTV's Pimp My Ride may be able to sponsor some solutions.
-http://www.mtv.com/thinkmtv/features/environment/pimp_my_green_ride/
- Specifically, I was thinking that the custom car shops that integrate computers into vehicles must have already solved many issues related to power (the engine) being off as well as the car battery not being drained by the electronics that they install.
-http://hardware.slashdot.org/article.pl?sid=01/10/25/208237&mode=thread
-I also designed and built my own custom power supply. This could be useful to people who want to take linux into their car. It is also useful for solar powered battery operations."
-Anyone who has owned or used a power inverter or more demanding electronics in a car knows that you really can't run it (for long) when the engine is off. An inverter will automatically shut itself off and turn itself on when the input voltage fluctuates (a sign that the engine has been turned off).
-Since the input voltage is only 12 volts, a easy battery backup could be implemented to allow the computer to run while the car is off. When the battery gets low, the computer automatically suspends or hibernates.
 ==Environmental==
@@ Line 217: / Line 102: @@
 The [[school server]] should meet higher drop and shake specifications than standard consumer
 desktop PCs, to account for rough transport in the delivery.
-=XSX Specifications=
-Right now, we using this term to refer to any hardware platform meeting the following criteria:
-* 1GHz+ x86 processor
-* 1 GB main memory
-* four to six USB interfaces, with power for three Marvell Wifi nodes and an external disk drive.
-* one 300GB+ 3.5in SATA drive (500 GB makes more sense right now)
-* power and space for a second disk drive
-* two 100baseT network interfaces (one will do in some cases)
-* minimal fans
-There are many hardware platforms meeting these specifications.  We are working on a recommendation for a low power version.

XS Server Hardware: Difference between revisions