Embedded Linux steals design wins
Contents
1. designfeature _By David Marsh Contributing Technical Editor LINUX SEEMS TO HAVE BEEN THE NEXT BIG THING IN EMBEDDED SYSTEMS FOR YEARS FINALLY IT IS BEGINNING TO PENETRATE THE EMBEDDED SYSTEMS MARKET VENDORS KEEN TO PROMOTE NEW MARKETS FOR THEIR SILICON NOW DRIVE INVESTMENT IN THE OS SO HOW EASY IS IT TO GET STARTED AND HOW USEFUL IS IT Embedded Linux steals design wins my suggestion to consider Linux for an em bedded system s user interface and superviso ry control met with a lukewarm response Objec tions ranged from Linux inability to respond to real time events through concerns about software support within the open source community to plain fear of the unknown and the group eventually chose Windows CE Back then it s fair to say that no derivatives of mainstream operating systems prop erly suited embedded development with the result that most designs employed proprietary solutions such as QNX Neutrino or Wind River s VxWorks Meantime the mainstream commercial and open source communities have been busy adopting their core software architectures to suit small footprint embedded systems with the result for example that at last February s 3GSM World Congress in dustry giants such as Infineon Philips Samsung and STMicroelectronics announced cell phone products that use Linux Elsewhere Freescale s software arm Metrowerks offers automotive strength Linux primarily for in car en2. OReilly Media series Reference 4 A re cent addition to O Reilly s catalogue is Karim Yaghmour s Building embedded Linux systems which painlessly com bines a great deal of information that would otherwise take endless Net search es to acquire The publisher also offers the third edition of Alessandro Rubini s now classic Linux device drivers handbook that s updated to cover the 2 6 x kernel But if the thought of navigating the open source community doesn t appeal there are numerous alternatives becom ing available that still provide cost effective entry level opportunities For example ADI has uClinux ports for the BF531 533 and 535 Blackfins that suit its EZ KIT hardware and VisualDSP de velopment environment It s also possible to marry the Stamp kit to VisualDSP for which a 90 day evaluation license is available www edn europe com designfeature Embedded Linux Michael O Donnell manager of core technologies marketing for Freescale s software subsidiary Metrowerks sum marises Linux penetration into the em bedded space by observing that back in 2000 there was considerable interest but little adoption Now his customers express great interest in real applica tions such as automotive infotainment O Donnell observes that the entire Linux business model is changing and that to day s heavy investors are semiconductor makers keen to establish new markets for their silic
3. just as EDNE was closing for press Qualcomm declared that it will support the Linux operating system on its mobile station modem MSM6550 chip sets According to its press release the company expects this move to give hand set makers additional design and devel opment efficiencies for 3G smartphones and other mobile handsets It notes that integrating Linux support into the chipsets eliminates the need for a separate coprocessor and lowers design costs and complexity compared with the multiple chip implementations that a third party OS currently requires Qualcomm also plans to extend Linux support to other chips in its enhanced multimedia plat form family including UMTS HSDPA and CDMA2000 derivatives REFERENCES 1 Marsh David Automotive design sets RTOS cost and performance chal lenges EDN Europe September 1999 pg 32 www edn europe com 2 Webb Warren Embedded Linux nears realtime EDN September 16th 2004 pg 55 www edn com 3 Path to pflags test example http cvs blackfin uclinux org cgi bin cvsweb cgi uClinux dist user blkfin test pflags test cvsroot uclinux533 4 Marsh David Linux applications cruise with new drivers Test amp Measurement World April 15th 2000 http www reed electronics com tmworld article CA187384 and The ins and outs of Linux kernel device drivers T amp MW October 15th 2000 http www reed electronics com tmworld article CA187432
4. www edn europe com
5. www gd ais com Infineon Technologies Www infineon com Www microsoft com MontaVista Software www mvista com O Reilly Media wwworeilly com 32 EDN EUROPE JUNE 2005 Nero Slackware Www nero com wwwslackware com Philips SolarWinds Net www philips com www solarwinds net QNX Software Systems Sun Microsystems www qnx com www sun com Qualcomm Suse Linux www qualcomm com www novell com linux suse RTAI Project Polytech STMicroelectronics nic of Milan depart ment of Aerospace En www st com gineering Volcano Communica www rtai org tions Technologies wwwwvolcanoautomotive com Red Hat Software www redhat com Wind River Systems www windriver com Samsung Www samsung com Xilinx www xilinx com improved boot times power manage ment and even though not a hard real time product for which Metrowerks recommends its OSEKturbo RTOS determinism O Donnell considers that stability is a key customer requirement not only in the software where customers often choose mature kernels over the lat est builds but also in the overall business model that facilitates ongoing development from mul tiple suppliers He concludes When Linux crosses the chasm and becomes more mainstream the busi ness model will mature to the embedded community s benefit Present indications from the stream of Linux related announcements suggest that this maturity will come soon For example
6. consider such issues as a newbie s rite of passage hence it s im perative to be prepared to dig and delve to get results and in reality there are a several full blown commercial products that are no less arcane The LAN connection requires a TFTP trivial file transfer protocol server running on the host such as the free for personal use TFTP Turbo Windows compatible software that the manual de scribes Alternative solutions include Free TFTP Server from network management specialists SolarWinds Net which is available as freeware Correct installation and setup cuts the download time for 6 491 055 bytes to about 18 seconds on the test PC when running the bootelf command loads and runs the kernel im age In case of doubt check the header information for the timestamp of the image that s now running but don t save any environment variables using U Boot s save command until certain www edn europe com designfeature Embedded Linux 26 PROS gt n Joas The network software defined oscilloscope project demonstrates a remotely controlled Web instru ment running under uClinux that they work correctly as this step flash es system memory Recovering from a bad Flash situation requires the user to reprogramme the memory via the Stamp board s JTAG interface employing a low cost parallel port wiggler The hardware schematics and software files appear at the ucLinux Blackfin po
7. etho Execution Finished eres www Lgsoftindia com 30 May 2004 cat etc motd Welcome to ott ther Snformat Lon see oy Fai uel inu rg http Z lackfin elina org 1fsogthg PI PHY 1 CANESC permease Seen 1 1 Internal f broadcast 10 44 2 255 up Sash command shell version 1 1 1 Auto demt SMO RAE ma configures the toolchain for the Stamp board taking upwards of 15 minutes on a 2 4 GHz Pentium 4 But don t forget to reserve investigating the SnapGear screen options for later as they allow quick ker nel rebuilds with alternative parameters The process concludes by depositing a file that s simply called linux not lin ux dxe in the uClinux dist linux 2 6 x directory This file is an executable amp linkable format ELF uClinux kernel image that users can download via the U Boot loader and run from the Stamp s SDRAM The Cygwin installation docu mentation doesn t explicitly tell you so but at this point the system is ready for its first use with the Stamp target It s then best to jump to U Boot s HyperT erminal section in the user manual which describes how to download the newly compiled kernel image and run it This is the least effort way for new users to ensure that the system is working but it takes about 1 5 hours to download the 6 3 Mbyte file over the test PC s 57 600 kbps Kermit protocol serial link AT A GLANCE gt Embedded Linux scores with major tele phony des
8. his own tests with MP3 decod ing reveal 5 processor loading hence there s considerable latitude for power management in portables Hennerich also directs developers at tention to the BusyBox programme that crams many familiar Unix facilities into a small footprint executable Requiring only a kernel image and the dev and etc filesystems BusyBox the Swiss army knife of embedded Linux furnishes the key GNU toolchain s core utilities that any embedded Linux system needs Sup plied as source code BusyBox is proces sor agnostic and allows users to include only those functions that the application requires Contributors to its code base in clude Linus Torvalds the creator of the Linux OS see www busybox net KERNEL MANIPULATION FOR 1 0 Because Linux handles all I O via de vice drivers getting the OS to do some thing useful requires writing and debug ging kernel level code The current Stamp documentation includes several pointers to help users accomplish this task as well as many helpful sections on issues such as using the make command and the gdb Linux debugger But the documentation package currently falls short of describing key issues that include application and driver development ADI advises that the documentation is under review and that new material will appear very soon ADI s Hennerich points to the pflag driver that appears on the portal as a simple example of an application that toggles
9. 2005 For engineers interested in applying Linux for applications as diverse as em bedded controls and infotainment con soles the recently released ADSP BF533 Stamp development kit from Analog Devices ADI makes interesting news For less than 200 the product compris es a target board a CDROM that contains the uClinux software and a universal input power supply just add a standard straight through serial cable and a host PC and the system is complete The board accommodates a single ADSP BF533 Blackfin 500 MHz processor along with a seemingly massive 128 Mbytes of SDRAM that s arranged in four banks of 16X4 Figure 1 This memory comple ment gives software writers sufficient lat itude for application development at a time when multimedia phones are de manding as much memory as some PCs For example Samsung has just an nounced a 4 Gbit flash memory that packs four 1 Gbit die into an 11X13 mm package The 1 8V device sustains data reads at 108 Mbytes sec four times faster than conventional NAND Flash devices and writes at 10 Mbytes sec which is over 60 times faster than stan dard NOR Flash The company plans mass production starting this July The Stamp board accommodates 4 Mbytes of Flash together with a CPLD that expands the processor s asynchro nous memory space to suit this maxi mum amount of Flash Various periph erals such as a 10 100 Mbit sec Ethernet port appear within the processor s asynchron
10. H8S 2100 from Renesas see http sourceforge net projects h8 uclinux LOW COST DEVELOPMENT SYSTEMS All of this may sound just great How ever the available choices make getting started with Linux a nontrivial exercise As all embedded development requires a host machine it s next to essential to have a desktop Linux installation see sidebar Is Linux fit for prime time If this choice is complex choosing an embedded platform is even more diffi cult For instance a search for embedded English language Linux at www linux org returns no less than 27 distributions for all platforms As for the desktop en vironment it s perfectly feasible and within the spirit of the Linux communi ty to download freely available files and compile your own installation En gineers with less time and more immedi ate focus are more likely to benefit from ready made development plat forms and again there s a wide choice For example Koan of fers a start up kit that includes the software documentation and the company s develop ment environment toolbox from 299 At the opposite end of the spectrum Arcturus Networks the professional developer of uClinux offers a reference platform for resi dential gateways and routers along with complete devel opment kits for Atmel s AT91 ARM7TDMLas well as for Freescale s ColdFire and DragonBall architectures at prices that span 495 to 1295 24 EDN EUROPE JUNE
11. alability But first time users need deter mination to build their own systems from Web resources whereas for typically less than 100 commercial distributions provide a package that s guar anteed to install relatively quick ly together with support docu mentation that s often quite good All such distributions contain similar core compo nents and mainly differ in the additional software that comes in the bundle such as graphical set up tools that augment tradi tional command line configura tion commands But it s worth checking which kernel version the distribution includes although the latest release isn t necessarily the most stable hence commercial users typically recommend using one that s a few issues old unless it s known to have serious flaws Another point that s worth con sidering is the distribution s ability to detect hardware Although the major vendors have improved their products installation routines significantly in recent years experience suggests using a PC that s as standard as possible not so long ago USB support was 26 EDN EUROPE JUNE 2005 flaky and it s only in the last month that an everyday Windows PC utility such as CDROM DVD burning software from Nero Germany s world leaders in PC optical writer soft ware has become available Notebook PC support is sup posedly available too but haven t yet dared to test this on a brand new Dell Inspiron that asto
12. e compo nents on a Linux host This approach short circuits tasks that first time users may find intimidating although the main user manual provides step by step instructions that show how to build the toolchain on a Linux box Running Cygwin s setup decompresses and installs a virgin system The set up procedure also installs the freeware AnyEdit text editor that can convert between Windows Cr Lf carriage re turn linefeed and Linux Lf end of line terminators other first time user issues to beware include Linux use of the for ward slash rather than Window s back slash for path direction Clicking on the Cygwin uClinux desktop icon then opens the system s command line interface win dow that s based on the Linux standard bash shell the Bourne again shell re placement for the shell that s used throughout the Unix world Next the Cygwin instructions walk the user through the make process that tailors the environment to the target board This step appears under the configuration screen s processor type and features submenu and defaults to the correct options for the Stamp target For first time use ignore the temptation to tam per with these screens that is simply select Save amp Exit when the SnapGear configuration screen appears then in voke the make command This triggers a lengthy script that builds the system and Bis ands 28 EDN EUROPE JUNE 2005 Zetc issue Command ig
13. echo cancellation card he says Another hardware consideration is Linux requirement for 32 bit machines There is a 16 bit project that targets 8086 type architectures at http elks sourceforge net but with the avail ability of 32 bit chips such as Atmel s AT91SAM7S family of ARM7 based Flash microcontrollers costing around 3 in volume it s pointless pursuing 16 bits for anything other than historical curiosity Of course Linux own history of devel opment on 386 machines means that it s easy to port into the 386 embedded space But there s also widespread support for ARM and PowerPC architectures along with various projects that include www edn europe com designfeature Embedded Linux target machines such as MIPS and 32 bit Renesas Super H devices that in clude MMUs The uClinux project www uclinux org makes it possible to run Linux on machines that lack MMUs which is significant for the embedded space where there s often little demand for multitasking Unlike many other Linux projects that currently appear fairly dormant uClinux is definitely alive and well In fact kernel version 2 6 includes features from this project with the result that it s now possible to run the OS on MMU less chips such as Analog Device s Blackfin the ARM7TDMI Freescale s 68k ColdFire and QUICC products Intel s i960 and NEC s V850E If you must have 16 bits there s even an active project for the
14. his issue is neither trivial nor covered in the documentation thus requir ing as is often the case a Web search to find help Sadly The Linux Network my favourite resource for Samba and Linux networks in general is currently out of print but still available see Reference A There s also some evidence of immature application level soft ware as the first attempt to build a search index within KDE s help system crashed the application but not the sys tem In many ways this experience reflects an impres sion of the Linux Windows divide experience here with kernel level development on a 2 4 installation confirms that it s very hard to crash or dam age Linux But it wasn t until Windows 2000 Professional that Microsoft produced an OS that rivals Linux s stability with Win 2K Pro demonstrating rock solid performance in over three years of intensive every day use Meantime it s easy to feel that the Linux camp has made little progress in easing its desktop into the mainstream beyond implementing numer ous me too features from its rival with the formerly clean lines of KDE increasingly adopt ing XP s look and feel But power users will appreciate the ability to tailor and continuously update their Linux systems with out being forced into the wholesale changes that have made XP unpopular in some quarters Crucially developers used to wrestling with system issues won t encounter any ins
15. ign wins Semiconductor vendors promote Linux to sell silicon Entry level hardware enables serious work for lt 200 Open source offers freedom but raises IP ownership issues Desktop OS adopts XP look amp feel Cygwin and HyperTerminal permit uClinux development and communications on a Windows PC host new instance of uClinux that s running out of SDRAM confirming that the system installation is healthy Figure 3 Because the serial link is so slow it s imperative to get the Ethernet commu nications working This requires connection into a LAN via a standard Ethernet RJ 45 cable or via a crossover cable di rectly into the host PC Again the docu mentation does not explicitly state that the Ethernet connection doesn t come alive until you invoke a U Boot command such as tftpboot at which point the on board Ethernet activity LEDs will light as will monitor LEDs in the LAN s switch Although obvious in retrospect this departure from standard LAN practice caused some consternation here that re sulted in swapping cables trying Ethernet crossover wiring and then scoping the Ethernet controller s chip select line while ping ing the network before the clue finally sunk in Similarly ping only works from the target to the server tim ing out in the opposite direction as there s no process implicitly running on the tar get to complete the handshake Linux vet erans invariably
16. on As a result the prime users are no longer Linux gurus and carry over their expectations from commercial em bedded development environments he says It s therefore imperative that soft ware vendors make embedded Linux easy to approach and use He characterises a typical development team for a project of any size comprising a couple each of ker nel and driver software writers and per haps as many as 20 application software writers For this reason it s essential to have an integrated development environ ment that allows engineers to seamlessly move from one project phase to another Customers are looking for hardware and board support packages that span evaluation and feasibility studies to ap plication software and kernel level de bugging in complex systems Metrowerks accordingly offers a range of products FOR MORE INFORMATION based on its CodeWarrior toolchain that suit Freescale s ARM ColdFire and PowerPC architectures Those products include the QUICCstart evaluation pack ages that bundle a development board the CodeWarrior integrated development environment a Linux board support package as well as the WireTAP run con trol tool for the PowerQUICC I II and III processors at prices ranging from 495 to 1095 O Donnell also notes that recent ColdFire silicon includes an MMU thereby facilitating a full Linux board support package for this variant Commenting on issues that continue to c
17. oncern customers O Donnell reports that intellectual property IP figures high on the list A recent due diligence search revealed around 50 styles of open source licensing arrangements leaving cus tomers wondering how best to partition their precious IP from public domain software Which licenses are included in the board support package and how do they interact with my IP is a ques tion that he s frequently heard especially from the traditionally conservative auto motive segment Metroworks released its automotive grade Linux to widespread interest at Detroit s Convergence 2004 show The technical lessons that the com pany learned in developing its product in clude the need for new versions to offer For more information on products such as those discussed in this article contact any of the following man ufacturers directly and please let them know you read about their products in EDN You can reach Contributing Technical Editor David Marsh at forncett btinternet com Analog Devices Koan Software Engi www analog com neering www koansoftware com Arcturus Networks wwwarcturusnetworks com LiveDevices wwwilivedevices com Digium www digium com LynuxWorks www lynuxworks com Freescale Semiconduc tor Mandriva www freescale com wWww mandriva com FSMLabs Metrowerks www fsmlabs com www metrowerks com General Dynamics Ad Microsoft vanced Information Systems
18. one of the Stamp board s LEDs terminating when the user presses the matching pushbut ton This example and many more reside within the portal s CVS concurrent ver sions system repositories Reference 3 One work of particular interest is the net work oscilloscope project that uses the ADC daughter card and open source dri ver software to demonstrate how to set up a Web server that remotely controls the instrument returning jpeg format traces to the host in either time or frequency do mains Figure 4 For this and any other serious development work Hennerich stresses the need for a proper Linux host Cygwin is suitable for test drives but serious developers should use a native Linux distribution He adds that he s working on another Cygwin release that s intended to show an I O port manipula tion as well as a replacement called coLinux that he recommends for future use on Windows systems coLinux runs a real Linux kernel complete with its file systems and case sensitivities on a Windows machine and will load native Linux applications Hennerich emphasis es that work is ongoing on support doc umentation and urges users to regularly check the Blackfin uClinux portal for updates to this and other packages Other available quick start resources include a series of features in EDN s sister publication Test amp Measurement World which also lists further resources such as several invaluable books from the
19. ous memory map space Oth er hardware highlights include three pushbutton switches and LED indicators Headers provide access to all peripherals while offering JTAG connectivity to programme the ADI Stamp board s Flash that the CPLD can map into GPIO space or disconnect and a multilevel switch mode power supply that displays the ca pabilities of ADTs ADP3025 controller chip Two headers that allow access to the Blackfin s and the CPLD s JTAG in terfaces complement the normal range of headers that access the microcontroller s peripherals Figure 2 These peripher als include two serial ports an SPI port a parallel port GPIO interface three timers a real time clock and an infra red device interface These features fit onto a four layer board that measures 178X127 mm An ADC daughter board is available and hardware now under development for which schematics are already freely available includes an audio codec card and a pair of video encoder decoder cards The CDROM contains the system s documentation including schematics and CPLD files and various software components A 130 page user manual that includes sections from Analog Devices and Arcturus Networks intro duces uClinux and documents the Stamp board It includes some tutorial material but is currently in the pre beta stage release 0 5 4 for updates check the user group pages at http blackfin uclinux org which is also the portal for support issue
20. owerPC and Xscale architectures principally for use within industrial controls Back in the consumer space the spate of infotainment and telephony applica tion announcements signals a trend for far more widespread embedded Linux adoption within devices that impose less severe demands on mission critical stur diness and real time response Of course Linux already has an enviable reputation for reliability and security that helps ex plain its recent choice for a joint venture between mobile phone operator Orange and STMicroelectronics where the OS runs a secure electronic cell phone pay ment application on STM s ARM based Nomadik processor But Linux tradi tional response time tardiness has been a barrier for many applications which has been due to the original kernel s non pre emptive design where run ning tasks suspend interrupts along with the use of a fairness algorithm for its scheduler that guarantees all tasks 22 EDN EUROPE JUNE 2005 a slice of processor time regardless of priority considerations This kernel also depends on page swaps between tasks which makes it impossible to accurately predict timing in systems that must ac commodate asynchronous events It also requires a memory management unit MMU for memory protection and to facilitate multitasking Today s version 2 6 of the kernel in cludes enhancements to reduce latency along with many embedded friendly fea tures including the option
21. rtal but details of the process are currently missing from the user manual signalling the need for care here At this point the user has a fully work ing uClinux development system It s then possible to recompile the kernel to reduce footprint from the command line or by using the SnapGear graphical interface a process that the user manual describes well Michael Hennerich European DSP systems and applications engineer at ADI Munich Germany and a leading architect of the uClinux Blackfin pro ject notes that the default root filesys tem size is around 4 Mbytes with the de fault kernel configuration occupying about another 1 Mbyte Users can adjust these footprints to suit their applications Hennerich also points to the U Boot loader s facility for compressing and de compressing Flash memory kernel im ages that can achieve as much as a five fold Flash memory saving at the cost of a slight increase in boot time and cites the Blackfin s dynamic power manage ment abilities that further optimise the processor for low power small footprint systems While kernel compilation per mits static changes to clock frequency parameters that default to 497 MHz core and 124 MHz system clocks a real application can dynamically vary the 30 EDN EUROPE JUNE 2005 clock frequency and core voltage to conserve power in portable electronics Hennerich says that it s premature to release formal benchmark results but says that
22. s The CDROM s software content includes pre built ker nel images and the source code the toolchain ports for the Blackfin a free distribution of JTAG tools the U Boot loader and a Blackfin port of the Cygwin environment A single sheet quick start guide satisfies users anxious to make something happen The first task is to establish PC to board communications using for instance HyperTerminal Follow the few instruc tions and the board powers up runs through some memory check routines and defaults to boot the kernel from onboard Flash The uClinux command shell screen duly appears within the HyperTerminal window To avoid the necessity of installing Linux on the host in the case of this evaluation a Windows XP Professional machine run ning SP2 on an NTFS www edn europe com designfeature Embedded Linux IS LINUX FIT FOR PRIME TIME As the main text asserts embedded Linux developers require a desktop instance And while Linux gurus promote their favourite installations newcomers often wonder what s different about packages from mainstream vendors such as Mandriva formerly Mandrake Red Hat Slackware and SuSE especially as it s pos sible to download and build an installation from for instance Debian www debian org or Fedora wwwfedoraproject org for free Interested users should also check out the less er known Gentoo www gen too org a Linux flavour that s expressly tuned for sc
23. tertainment applications And just last month Xilinx announced a Linux port for its freely downloadable Webpack FPGA development environment signalling the OS s increasing acceptance within the engineering fraternity So just how useful is Linux for embedded development and equally importantly how easy is it to get started First off it s essential to differentiate between hard real time operating systems that guarantee no missing deadlines and where timelines are exactly A a design review meeting five short years ago 20 EDN EUROPE JUNE 2005 known and soft real time systems that on average perform tasks within a specified timeframe Envi ronments such as QNX VxWorks and a host of others such as the Realogy suite from LiveDevices and Volcano s automotive networking series tackle mission critical applications where fully determinis tic response is essential Reference 1 But as EDN s Warren Webb recently reported there are a number of commercial Linux products that target real time needs such as BlueCat Linux from LynuxWorks that complements its LynxOS and the forthcoming Red Hat Embedded Linux a cooperative effort from Linux stalwarts Red Hat and the biggest com mercial RTOS vendor Wind River that har monises Linux and VxWorks Reference 2 Proof that these developments mean business comes from recent announcements such as General Dynamics Advanced Information Systems selection of Lynu
24. to build small footprint kernels for devices that don t require user interfaces Included in kernel releases from the interim version 2 5 the heart of the system is the so called O 1 scheduler that adds kernel pre emption task priorities and a dedicated time slicer Mark Spencer president of Linux based telephony systems builder Digium re ports that the OS s performance is fine for soft real time applications without additional kernel modifications Most modern PC platforms can handle as many as 1 000 hardware interrupts sec which is adequate for the time division multiplex busses at the core of Digium s Asterisk system he says He considers that one of Linux key advantages is its ability to scale from tiny embedded plat forms to supercomputers and parallels its development with that of the PC In the beginning PCs just ran word processors and spreadsheets but they soon began to displace minicomputers and domi nate the computing landscape Linux is becoming similarly pervasive with prod ucts now appearing in hugely diverse application areas Spencer observes that Digium s continuous development of its open source Asterisk offering which the company can also license to third parties for proprietary software development typifies the Linux commercial fraternity s business model We ve just launched Asterisk Business Edition and are work ing on more PBX infrastructure hard ware including an
25. undingly lacks re install disks for its Windows XP and driver software Historically Linux notebook support has been inadequate at best hence the test PC in this evaluation is a conventional desktop that has a MicroStar International motherboard with a 2 4 GHz Pentium 4 512 Mbytes of RAM and the AMI bios Peripherals comprise two IDE interface 80 Gbyte hard disks serial ATA apparently still suffers from immature support under Linux a Sony DVD CDROM reader and companion DVD writer an Acer multimedia USB key board a Microsoft PS 2 mouse and an NVidia GeForce4 MX440 graphics adapter driving an liyama Vision Master Pro moni tor The resident OS is Windows XP Pro The ADI Stamp documentation see main text shows SuSE screens reflecting the fact that this distribution from Novell s German subsidiary is Europe s leading implementation As the release of the much awaited version 9 3 of SuSE Professional arrived just in time for this edi tion of EDNE it s the natural choice for a test drive The package comprises two DVDs and five CD ROMs that replicate the installation and application binaries and source code a 280 page user guide and a 680 page administration guide that contains installation and system configuration informa tion Application software includes a range of database graphics Internet email mobili ty multimedia office and secu rity applications as well as the KDE and Gnome desktop en
26. urmountable difficulties and will soon come to love the Linux environment especially with its open access to the tech nology but it still isn t a breeze Reference A Butzen Fred amp C Hilton The Linux network IDG Books ISBN 1 555828 589 X Out of print but still available see www amazon com www edn europe com designfeature Embedded Linux format drive users can install Pe Ct ve Cal Daie feet Cygwin a Linux like environ DS TEIE When the HyperTerminal screen returns typing ment for PCs www cygwin com As its home page fore p Invoked to run tor etc rc command hostname blackf inetd cat etc issueS 2 mouse device commo bootelf 0x1000000 should reward patience with a warns Cygwin is not a way to run native Linux applica tions on Windows or to make Windows aware of Unix func tions You have to rebuild your application from source if you want to get it running on Windows But this restriction is irrelevant in the embedded a context where every change to mastaaa the target requires recom pilation The Cygwin in structions that accompany the kit also estimate that this port is around three times slower than a native Linux version It s no lightweight installation either occupying almost 1 Gbyte of disk space But the Blackfin port of Cygwin includes the toolchain and the uClinux kernel which avoids the requirement to download and build thes
27. vi ronments and masses of devel opment tools Caution dictates backing up the Windows installation before creating a spare 10 Gbyte area on the second hard drive Install options include the grub boot loader that allows the system to start Linux or Windows the KDE desktop and all Linux development tools making the installation size about 4 7 Gbytes The only step nec essary to install from DVD was to enable bios legacy USB sup port to enable the installer to recognise the keyboard Checking the hardware tool confirms that the installer cor rectly identifies the system s components The installer automatically found the LAN and established an Internet connection via the network s ADSL router using DHCP dynamic host configuration protocol connecting into Novell and updating SuSE with recent patches But confirming the experience of nearly 10 years of working with Linux this is where imme diate reward stops Certainly if you just want to run the integral OpenOffice development of the excellent StarOffice suite that Sun Microsystems hosts the Linux desktop is a comfortable place But try to connect a Linux box to a WinNT4 server net work and it s still necessary to grapple with the often arcane internals of Samba the Unix to DOS OS2 Windows LAN bridge software Plus simply clicking on the network icon to browse returns the unhelpful error mes sage lisa daemon not installed or running Resolving t
28. x Works LynxOS 178 safety critical RTOS for the US Army s future combat systems FCS infrastructure While such systems are Linux compatible they inevitably employ proprietary software to fulfil cus tomer needs For example MontaVista s modifica tions to the Linux kernel for its carrier grade prod uct add numerous pre emption points to improve worst case latency from gt 100 msec to lt 1 msec to suit use within telecoms infrastructures Alterna tively RTLinuxPro from FSMLabs runs Linux as an idle thread under supervision from a hard real time OS core that guarantees worst case interrupt laten cies of 13 psec on a typical x86 platform while permitting seamless access to the Linux environ ment European interest comes from Italian software www edn europe com designfeature Embedded Linux Power 10 100 Ethernet ADDR DATA ADSP BF533 Expansion Connector Address 1 19 Data 0 15 FLASH 2Meg x 16 Address 20 21 The Stamp board from Analog Devices enables Linux development via a 500 MHz Blackfin microcontroller and 128 Mbytes of SDRAM developers Koan whose Klinux uses the real time application interface RTAI kernel extensions from the RTAI Project at the Polytechnic of Milan s aerospace engineering department to furnish hard real time response Available under roy alty free open source conditions Koan specialises in porting its system to proces sors including x86 ARM P
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