I have a BBB running on angstrom. I want to increase the storage space, for that purpose I am using an SD card. The problem here is the angstrom images tries to boot from SD card if there is an card available on the slot and gets hang there as I am using that card only for storage purpose.
So how can I change the behavior of booting, or how can I disable the option of booting from SD card so that I can keep an SD card in the slot at boot time and boot BBB always from the emmc image.
Main objective is to boot bbb from emmc image even if there is an SD card present in the SD slot
That sounds like a very very old U-Boot and thus probably also very old Ångström. Personally I'd upgrade that (as that also happens to get rid of what you are experiencing).
If you want to stick to the current setup, you'll have to figure out how to change the U-Boot environment variables to always point to the right storage device, or check if updating U-Boot would help.
One way, which is specific to your question and setup, would be to change the device name referred to in the environment. (If you insert a SD-card, it becomes the first device instead of the eMMC) You can probably find hints on the eLinux Wiki, but keep in mind that your U-Boot is ooold.
For this you just need to have a uEnv.txt in SD card to stop BBB booting from SD card even if it is plugged at boot time. The content of uEnv.txt should be, make sure to write this file in linux Env.
mmcdev=1
bootpart=1:2
mmcroot=/dev/mmcblk1p2 ro
optargs=quiet
Related
Im developing an uwp app on Raspberry Pi 3 with Windows IOT Core. But after I deploy my app and use it for couple days the os crashes. It says something went wrong. It says "Your pc ran into a problem and needs to restart". It restarts couple times but still same error on every boot.
I tried to remove the sd card(Class 10,64 GB) format it and reinstall everything. At first it was okay but after some time same error appears.
I tried to use different os builds and it didnt work.
I tried to use industrial power supply (5V3A) and also it didnt work.
My SD Card is not one of the recommended ones but do I really have to get the recommended sd cards to use the windows iot core properly?
"Your PC ran into a problem and needs to restart" is a typical blue screen message seen on Windows systems from the last few years - laptops and desktops with far larger hard drives and no SD card. The error is not associated with a RAM or disk space shortage (operating systems running in graphical mode usually monitor and actively warn about either). In your case, it is showing at startup, when not much is running (taking up RAM), and you can check the amount of space used on the card with the PC.
The key stats for SD cards are size (you have plenty) and speed (clearly enough or you would have trouble installing/running anything after starting the Pi). The cause is something else, and finding out what will require getting a more detailed error message from Windows - "a problem" could mean anything. In my experience, blue screen errors have mostly involved having a wrong driver installed, sometimes a bad Windows update - but IoT Core has its own alternatives, like "bad system configuration". Look for the underscored string (e.g., BAD_SYSTEM_CONFIG_INFO) at the end of your blue screen message, as that is the first hint.
Unfortunately, most Windows BSoD documentation is for traditional PCs, so I cannot recommend specific troubleshooting tools and be sure that they will run on the Pi.
You can use Windows Debugger to debug the kernel and drivers on Windows IoT Core. WinDbg is a very powerful debugger that most Windows developers are familiar with. Or you can also refer to this topic in MSDN, it shows how to create the dump file when the app crashes. If possible, you can share your code so that we can reproduce the issue.
I'm trying to write a OS for my own use, I want to show a blank (black) screen with VGA output but I have some problems(questions):
Under FAT32, I have MBR bootloader to read the first sector of the virtual disk image generated by bximage from Bochs. Where (which sector) should I put the second compiled code that shows the black screen? How to do it with dd utility? My second compiled code file is 9 Bytes only.
Is VBR necessary?
How do I know where the data region (FAT32) starts and ends?
I rewrote the bootloader provided from this link.
My disk file specifications is:
20M,
CHS 40/16/63
In chronological order...
Originally there were no hard disks and (if you weren't using "BASIC in ROM") computers booted from a floppy disk. In this case the first sector of the volume (the floppy disk) contains the operating system's boot loader.
Not long after hard disks got added, and worked using a similar scheme (where the first sector of the volume/hard disk contains the operating system's boot loader).
However, people soon realised that using a whole "large" hard disk for a single volume is silly/inflexible; so a partitioning scheme was invented to split the hard disk into multiple volumes. In this case the first sector of the disk (the MBR) contains a partition table where one is marked as the "active" partition, and some code to "chain load" the first sector of the active partition (the boot loader). This became "extremely standard", then people extended it to support multiple different operating systems, and most boot managers support multiple operating systems using this method.
Note 1: I define "boot manager" as something you use to choose which OS to boot, and "boot loader" as something designed to boot the specific OS that was chosen. Ideally these have nothing to do with each other, the boot manager should have nothing to do with any OS, and the end user should be able to change the boot manager with anything they like without upsetting or effecting any OS or any boot loader. Sadly, (for Windows) Microsoft are hostile towards allowing multiple different operating systems to boot using simple, sane and well supported methods (including allowing multiple instances of the same version of Windows to be installed at the same time, which could be useful - e.g. one OS for your work stuff and a separate OS for your kids both installed on the same computer) and try to smother sanity with their own "boot.ini" idiocy that mostly just makes everything horrid for no benefit (other than giving Microsoft more control over what you do with your computer). Of course when the user is only installing one OS on the computer it's nice for the OS installer to (optionally, if and only if the user wants it - e.g. because they don't already have their own boot manager) provide and install a minimal MBR that doesn't nothing more than chain load the operating system's boot loader.
As time passed more devices got added. The first was network cards and the ability to boot from network. This is nothing like "boot from disk". Instead, the network card's ROM (after some negotiation with a DHCP server) downloads an entire "boot file" (which is not limited to 1 sector and can be 500 KiB if you like) from a server, then provides an API (which became known as the "PXE API") that the boot loader can use to access networking (e.g. send/receive packets, download more files using the TFTP protocol, etc).
The other type of device that got added was CD-ROM. For these, a new specification ("El Torito bootable CD-ROM specification") was created, partly so that you could have a boot catalogue with multiple entries for multiple architectures (e.g. one for "80x86 PC", one for "PowerPC", etc) and let the firmware choose the most appropriate boot loader for the computer being booted. For this there are 3 methods for PCs - emulate a floppy disk, emulate a hard disk, or "no emulation". The emulation options work the same as original "boot from disk" method (and use 512-byte sectors, etc), but are limited and slow and probably shouldn't be used for anything other than compatibility with legacy operating systems. For "no emulation" it's completely different to the original "boot from disk" method, firmware is supposed to load an entire "boot file" (which is not limited to 1 sector and can be 500 KiB if you like), and sectors will be 2048 bytes (and not 512 bytes).
Even later; UEFI got invented. For 80x86 PCs this comes in 2 flavours - 32-bit 80x86 and 64-bit 80x86. In theory you can have a 64-bit UEFI boot loader that switches to protected mode/32-bit and starts a 32-bit OS; and you can have a 32-bit UEFI boot loader that switches to long mode/64-bit and starts a 64-bit OS. However, 32-bit UEFI is very rare (a few old Apple Mac's and almost nothing else) and these computers are likely to also support "BIOS compatible boot"; and isn't worth supporting 32-bit UEFI for that reason. For UEFI in general, it loads and executes an entire file (from whatever the boot device was) and provides an API that the boot loader can use (e.g. to setup a video mode, get a memory map, load other file/s, etc).
Note 2: UEFI tries to make it so that boot works the same regardless of which type of device you're booting from. In practice this doesn't work very well and you'll probably want a different boot loader for CD (that accesses file/s on the CD itself and isn't restricted to a weeny FAT file system image) and a different boot loader for network (even if it's only to allow you to pass IP addresses to the OS and avoid repeating the slow DHCP stuff after the OS boots).
With UEFI a new partitioning scheme was also introduced (GPT or "GUID Partition Table"). This has multiple advantages and (for new operating systems being installed as the only OS on a computer) should probably be considered the default (and the old "MBR partitions" should probably be considered obsolete for compatibility with old operating systems only).
Mostly; for 80x86 you'll probably need 4 or more different boot loaders:
one for BIOS and un-partitioned disk devices (floppy)
one for BIOS and disk devices that were partitioned with "MBR partitions"
one for BIOS and disk devices that were partitioned with "GPT partitions"
one for BIOS and network boot/PXE
one for BIOS and "no emulation" CD boot
one for 64-bit UEFI disk
one for 64-bit UEFI CD-ROM
one for 64-bit UEFI network
Of course all of these cases are "different enough" that it's silly to try to have a generic boot loader that covers multiple different cases (and in cases where there are similarities things like "512-bytes only" restrictions are so limiting that you'll be doomed if you try).
I'd also "strongly recommend" having some kind of abstraction between boot loader and the rest of the OS (e.g. a "boot protocol" defined for the OS that describes how a boot loader sets things up, passes information to the OS and transfers control to the OS); such that none of the code in the entire OS needs to know or care what the firmware was (if it was BIOS or UEFI or something else, like maybe kexec()). This means that anyone can create more boot loaders (to support other cases and other devices); and (as long as everything complies with your abstraction's specification) the entire OS will work with the new boot loader/s without any changes.
Under FAT32, I have MBR bootloader to read the first sector of the virtual disk image generated by bximage from Bochs. Where (which sector) should I put the second compiled code that shows the black screen? How to do it with dd utility? My second compiled code file is 9 Bytes only.
This is mostly wrong. For "BIOS hard disk" you should have an MBR (that has nothing to do with the OS at all) and partitions, and your operating system's boot loader should begin in the first sector of the partition (and should be designed to use DS:SI to find the partition table entry that describes its partition, and dl to determine which device the partition is on).
Is VBR necessary?
For some cases (booting from UEFI, network, CD-ROM) a VBR doesn't make sense. For some cases (booting from BIOS hard disk or BIOS USB flash) it's "theoretically optional" but extremely recommended; because some BIOSes may not recognise it (especially for the USB flash case), and other operating systems will assume that the disk isn't formatted (and will tell their users that the disk needs to be initialised/partitioned, convincing the user that your OS is garbage and leading to the user accidentally or intentionally wiping your OS off the disk).
How do I know where the data region (FAT32) starts and ends?
For FAT; there's fields in the BPB ("BIOS Parameter Block", which is misnamed as it's mostly not used by the BIOS at all) in the first sector of the volume/partition that tell you things like how many reserved sectors there are, how many sectors are in each cluster, etc. Really, if you're going to use one of the world's worst file systems for inappropriate things (e.g. for an operating system's main partition where things like effective permissions/security and fault tolerance are sorely needed) then you'll need to learn everything about FAT32 so that you can write code to allow the OS to support it after boot.
We have an application that allows a CC Reader (such as the MSR206) to be swiped to enter in a credit card number.
These magnetic swipe readers essentially just dump whatever data is on the card to the screen cursur, as if it was typed.
For example, if you had notepad open, and you swiped a card, then it would output the data into notepad. There is no programming necessary, except to parse the data, etc.
I recently purchased the MSR605, which can write as well as read cards. However, I am unable to get it to read info from the cards, unless I have their software open, which sets the card reader to "Read Mode".
Is there a way to utilized a Magnetic Reader/Writer like the MSR605 as a simple reader?
In the MSR Programmers Manual, it states the following:
"1. Power on your system (PC).
2. Setup the usb driver(for windows xp or vista) and Setup the driver for MSR605,all driver in the cd.
3. Connect USB of the MSR605 signal cable to a free serial port .
4. Connect Power-in cable to Power supply and AC receptacle (110V~240V).
5. Now you can use the MSR605 like MSR206."
However, I have not been able to get that to work. I setup the driver, and it still does not read, unless I open the separate program, and even then, it only reads into the windows in the MSR605.
You need to down load the MSR605 software its a program you can get for free if you go onca web site that sells them it will say software next to what machine you have it won't work with out it
I understand that the computer loads the first sector of memory known as BIOS, which runs diagnostics on hardware and the proceeds to load the OS. I guess my question leans towards the hardware side. How does the computer know which memory to boot from (RAM, ROM, FLASH, etc). I understand the differences between memory and I understand computers boot from the hard drive, but Im attempting to make an 8 bit computer with a z80 microprocessor, which will need to boot from ROM or Flash memory. The only problem is that the processor reads only from whatever memory the address pins are connected to and there are no separate address pins for ram and rom. Its also impractical to run the system on rom or flash due to the much slower read/write time compared to ram. The z80 to the best of my knowledge doesnt have separate commands for reading from rom and ram, and it wouldnt matter even if it did because the ram will be blank upon powering up. How does a computer choose to read from rom only upon booting and then switch to ram once the OS has been loaded. Is it hardwired in using logic gates? And how does a computer choose to write to flash memory or a hard drive instead of ram once the OS has been loaded? Would flash memory be treated as a device? Or is this also hardwired into the motherboard using logic gates? Sorry for giving so much background, I just dont want you to waste your time explaining things Ive already grasped. Ive just researched this to a great extent and thought about it for hours on end and cant seem to figure it out, and everywhere Ive looked doesnt explain how the computer chooses which memory to read from, it just says that it does. Thanks
I'm not sure I'm answering what you are asking, but I'll give it a try.
Some computers (at least, IBM PC-compatible computers), after powering up, usually run this BIOS (Basic Input/Output System) program. For this to happen, to the best of my knowledge, the hardware must make the jump to this code, and this code must be accessible (that is, mapped) from the physical memory, since that's where the CPU will execute code from. So, a physical address space with some read-only areas where this code is hard-wired to would do the trick.
Once the BIOS code is running, it can select how to proceed next. It can copy a sector from a hard disk to memory, (or a bunch of data from a Flash drive) and then jump to it, or whatever. That's up to the BIOS writer.
I will try to explain the Pentium boot up process very briefly.
On the flash ROM mounted on the Motherboard. there is a small program called BIOS (basic input, output system). After pressing the power button the BIOS program is executed.
The BIOS contains low level software that performs the following operations :-
checks how much RAM is installed and if all other PCI and ISA buses peripherals are connected.
it checks if all IO devices are connected.
scans a list of boot devices and selects the boot devices based on BIOS configurations setup earlier by the user.
once the boot devices is selected. the first sector from the boot device is read into memory and executed. it contains a simple program which examines the partition table and selects the Active one (Holding the OS). The secondary bootloader is read from that partition. this loader then reads the OS from the partition into the memory and runs it. After running, the OS asks the BIOS for the configuration info for each device and configure the new devices (those have no stored configurations). after all devices configurations are set. they are delivered to the kernel. Then it initializes tables, background boot up processes and starts login program or GUI.
I am working in a technology Laboratory. We have 15 BBB, an suddenly, 5 of them didn't power on any more.
They stay with the power on Led on, but nothing more happens.
Picture:
What can i solve the problem?
Thank you
Prior to solve the problem, you probably have to investigate it first.
I would verify those beaglebones are still functional:
That is, checking if the beaglebone black is displaying any messages on the serial console,
The procedure for connecting a USB-to-TTL adapter is described here.
I would strongly suggest to buy the exact adapter featured in the article above on e-bay
if you don't have one.
If there were no messages displayed on the serial console, I would attempt to load u-boot from the serial port.
This can be done by connecting both P8.44/SYS_BOOT3/LCD_DATA3/GPIO2_9
and P8.43/SYS_BOOT2/LCD_DATA2/GPIO2_8 to the ground (two of P9.43/P9.44/P9.45/P9.46) using two 4.7 k
ohm resistors, powering the beaglebone with an external 5V power supply (not by USB),
and power-cycling the beaglebone - power-cycling IS required, performing a 'reset' is
not enough for the new SYSBOOT configuration to be taken into account.
You can then download u-boot from your PC using Teraterm: u-boot-spl-.bin should
be downloaded using x-modem, and u-boot.bin using y-modem, as described in the
'Boot over UART' section of this TI wiki article.
Once you have u-boot running, you should be able to reinstall your beaglebone using information available on the Internet.
If you cannot boot using the boot ROM and the serial port, this would probably be a bad sign.
I would suggest to try the procedure for loading u-boot from the serial port with a beaglebone you know is working, this is totally non-intrusive providing that you don't modify the eMMC from u-boot.