Is there anyway that you can expose local partition or disk image through your computer usb to another computer to appear like external drive on mac/linux/bsd system ?
I'm trying to play with something like kernel development and I need one system for compiling and other for restarting/testing.
With USB: Not a chance. USB is unidirectional, and your development system has no way of emulating a mass storage device, or any kind of other USB device.
With Firewire: Theoretically. (This is what Apple's target disk mode is using.) However, I can't find a readily available solution for that.
I'd advice you to try either virtualization or network boot. VirtualBox is free and open software, and has a variety of command line options, which means it can be scripted. Network boot takes a little effort to set up, but can work really well.
Yet another option, is to use a minimal Linux distribution as a bootstrap which sets up the environment you want, and then uses kexec to launch your kernel, possibly with GRUB as an intermediary step.
What kind of kernel are you fiddling with? If it's your own code, will the kernel operate in real or protected mode? Do you strictly need disk access, or do you just want to boot the actual kernel?
Related
I'm planning on making a bootable USB, but first I have some questions regarding it, you can answer any of the questions you like.
Can a bootable USB access a hard drive where windows is installed on without password?
What is the safest OS for a bootable USB?
Which OS is the freeest (as in editing the source code and such)
If you create and boot the system from a USB is not much different from normal one, the only difference is in kernel, on hardware abstraction layer (this is handled by OS) and data transfer speed.
Yes, as long as the OS from USB have SATA (or whatever you have) driver and accept your HDD partitions format (NTFS/EXT etc). It doesn't matter if you have or not password but to have the data unencrypted. (usually user personal's folders are encrypted).
Safest.. no one is safer than another.
Mainly any Linux distribution.
I will recommend Ubuntu because it have the biggest community.
I'm interested in PC firmware programming, and am just studying the UEFI spec. To my surprise, it seems like a spec for an entire OS which is embedded in firmware. You can even write UEFI "applications", which run directly using the UEFI boot services, without any other OS present.
I've found blog posts which show how to create a "Hello, world!" application which can run in the UEFI preboot environment. This is... interesting, and bizarre at the same time. I'll run my "Hello, world" programs on a regular OS, thank you.
What kind of use cases are UEFI applications actually good for? Fancy boot configuration screens? Does any "real", commercially available PC firmware use UEFI applications to implement anything more than just boot loaders and boot configuration utilities?
Anything that isn't PEI/DXE/SMM core or driver is an application, so any "real" PC have them, because BIOS Setup is actually an UEFI application. Some vendors include various other apps like firmware updaters, diagnostic and troubleshooting utilities, etc. UEFI 2.4 makes possible to add your own application with a properly filled BootXXXX/KeyXXXX variable pair and then run it by pressing a key combination during POST.
Most console applications written in C can be compiled as UEFI application by using StdLib package of current EFI Development Kit and then run in UEFI shell.
Major examples of useful UEFI apps (besides bootloaders, shell and Linux kernel, of course) are Intel ME System Tools, Read Universal, Python 2.7 and many more.
Eventually, when legacy boot will not be available anymore, all currently useful DOS utilities must either be made UEFI applications or go extinct.
Despite many valuable answers here, because I wrote couple UEFI applications myself I will try to add my 2 cents. First, what is UEFI application to just give ground what we talking about:
UEFI Specificatin v2.5:
Section 2.1.1
The major differences between image types are the memory type that the firmware
will load the image into, and the action taken when the image’s entry point exits or returns. An
application image is always unloaded when control is returned from the image’s entry point.
Section 2.1.2
When the application returns from
its entry point, or when it calls the Boot Service EFI_BOOT_SERVICES.Exit(), the application
is unloaded from memory and control is returned to the UEFI component that loaded the application.
Groups of applications that make sense in UEFI:
Configuration tools - Configuration interface for Option ROMs (ie. for storage controllers), out of band management (ie. AMT configuration tools), manufacturer performance tweaking tools
Provisioning tools - used by administrators to preload specific BIOS setting, manually setting all options in BIOS setup would be inefficient
Diagnostics tools - mostly for tests that cannot be performed in OS (DRAM tests, full storage scan, storage R/W tests, etc.). In some districts specific diagnostics tools are required in UEFI BIOS, so those can be sold to government.
Security applications - HDD encryption/decryption, antivirus scanner and anti thief applications
BIOS capability enhancement - Power Over Ethernet extensions, DRAM discovery, patching and modification of system tables (SMBIOS, ACPI)
Display tools - for displaying complex animations while running, splash screen displaying
Bootloaders - this is special type of application, which can call EFI_BOOT_SERVICES.ExitBootServices() causing termination of all memory management and passing control to Operating System.
Note that very important feature of UEFI application is that it can be added to boot order and be executed each boot time. Also UEFI application do not have to be delivered with BIOS image it can be stored in connected device memory, which is common for Option ROM configuration tools.
Here it is an example of a full blown UEFI Pre-boot Application;
There are SED SSD/HDD drives. As soon as SSD/HDD loses its power it goes into locked state (hardware-based encryption) There is no way you can get access to drive's data and all partitions on the drive are no longer even visible. Only small read-only partition (ShadowMBR) is available. UEFI firmware boots an UEFI application from that only available partition (UEFI app is written on that partition during the initialization process and when the ownership of an SED is taken). It securely authenticate user and if credentials are valid it unlocks the drive. When the drive is unlocked Shadow MBR disappears and all partitions on the drive becomes available. Then the App chain-boots the installed OS.
So if you don't have credentials you cannot even boot the OS and you cannot access the data on the drive by any means.
Here's a couple of examples:
https://github.com/NikolajSchlej/CrScreenshotDxe
UEFI DXE driver to take screenshots from GOP-compatible graphic console (yes, you can make PNG screenshots of your BIOS and save them)
http://ruexe.blogspot.com/
RU.EFI is quite an advanced tool for debugging the BIOS
Well, there are the OS loaders - both the more heavyweight ones (Windows, GRUB, BSD Loader) and the "present a menu" ones (rEFInd, Gummiboot). Shim, which enables UEFI Secure Boot for Linux platforms, consists of an application as well as installing a protocol for use by other applications.
Then you have things like the Linux kernel, which when compiled with CONFIG_EFI_STUB becomes a valid UEFI application, with the awareness of booting itself.
And firmware updates can also be shipped as UEFI applications.
The UEFI shell itself is an application.
Then there are things like factory production testing utilities, development diagnosis tools, ...
Windows 7 - 8 have UEFI installer. I'm not fully aware of the details, but I'm pretty sure this new environment gives a lot more flexibility to the developers than traditional boot environment on DVD.
Some motherboards have "instant on" features that allows you to get to a desktop screen within a few seconds. This is usually a stripped down flavor of some linux that allows you to access a web browser and play music/video. ASUS have such boards.
I know how to change boot order through bios settings, but I have a unique situation where doing it programatically would be better. The company I work for sells and supports software remotely to thousands of non tech savvy customers. We can't touch their hardware settings, we are only the software vendor.
Recently we rolled out a option for their PCI compliancy that requires a separate removable drive to store a private encryption key. Customers that use this option have to leave a usb drive with a .dat file containing the RSA key at all times. Currently this presents an issue when customers reboot. Sometimes we can walk them through over the phone how to change their bios settings to skip the USB drive, but in many circumstances we cannot, because of the caller and the other end of the phone not being tech savvy enough to change bios settings, and different PC's having different BIOS setups.
So my question is, is there any kind of ini file I can create or boot record on the disk itself than can be added or changed to cause the system to see that there is no OS on the USB, keep going down the list of boot drives. Instead, with no OS many PC's hang on Missing OS screen until we have customer remove drive reboot and plug back in after Windows starts to load. All PC's are Windows, all XP or newer.
You're talking about manipulating BIOS Setup data. Unfortunately there is no industry-standard for computers to manipulate Setup fields, like the boot sequence, so any solution is likely to be vendor-specific.
An example: Dell Inc. provides customers OpenManage Client Instrumentation (OMCI) that allows admins to remotely change settings, like boot sequence, via standard interfaces like CIM/WMI. See this whitepaper:
http://www.dell.com/downloads/global/solutions/omci_info.pdf
Especially:
OMCI is the Dell instrumentation package that enables OptiPlex™, Dell
Precision™, and Latitude™ systems to be managed remotely. OMCI
contains the underlying driver set that collects system information
from a number of different sources on the client computer, including
the BIOS, CMOS, System Management BIOS (SMBIOS), System Management
Interface (SMI), operating system, APIs, DLLs, and registry settings.
OMCI exposes that information through the CIMOM interface of the WMI
stack. Thus, OMCI enables IT administrators to remotely collect asset
information, modify CMOS settings, ...
OMCI is specific to the Dell BIOS, so it won't work with other vendors' machines. Other enterprise hardware vendors (e.g. HP, IBM) provide similar software. If you can live with a vendor-specific solution, this may work for you.
May I ask if your USB is actually non-bootable?
How did you format it? FAT32, NTFS etc?
Why can't Windows bypass this usb when booting normally when (i assume) it is not bootable. Normally my system boots to Windows OS even if there is a non-bootable usb plugged in.
BTW have you tried keeping the DAT file on usb as hidden, read only, it's worth a try.
We are developing an embedded system which will use a PC motherboard running Linux or Windows Embedded (have not decided which one). The board will read data from FPGA via PCI Express.
Novice question: do we have to develop our own PCIe driver or we can use something from the operating system? If we need our own, can you recommend a resource?
It really depends on what kind of data you want to transfer with the device. If you just want register read/write you could just mmap /dev/mem and have a user space driver.
If you need to do DMA or interrupt then you'd likely have to write your custom driver.
Yes, unless your device corresponds to a standard device profile, you will need a custom device driver. Because you have not selected your operating system yet, your question about resources is pretty wide open still since obviously the OS selection directly affects driver design. For Windows you probably want to start here. Under Linux, perhaps here.
I have been tasked with writing a USB driver for our embedded software to send raw data to Host. This will be used to send some logging data to host. We are using iMX31 litekit for development.
From the documents that I have read on USB, my understanding is that the embedded device will be in device mode only. Also it will only be communicating with host machine.
So can any one guide me here? Any article, reference or code is welcome.
Some things to consider:
Is this a high bandwidth device like a camera or data recorder, or a low bandwidth device?
For low bandwidth, I would strongly consider making your device act as a USB HID class. This is the device class that supports keyboards, mice, joysticks, gamepads, and the like. It is relatively easy to send data to nearly any application, and it generally doesn't require that you write a custom device driver on the host side. That latter feature alone is often worth the cost of lightly contorting your data into the shape assumed by the HID class. All the desktop operating systems that do USB can use HID devices, so you get broad compatibility fairly easily.
For high bandwidth, you would still be better served if your device fits one of the well established device classes, where a stock device driver on the host end of the wire can be used. One approach that often works is to use the Mass Storage class, and emulate a disk drive containing one file. Then, your device simply mounts on the host as if it were a disk, and you communicate by reading and writing to one (or a few) file.
I would expect there to be a fair amount of sample code out there for any serious USB device chipset that implements either or both of HID and Mass Storage.
If you really must wander into fully custom device territory, then you will need to be building device drivers for each host platform. The open source libusb library can be of some help, if its license is compatible with your project. There are also ways in newer versions of Windows to develop USB drivers that run in user mode using the User Mode Driver Framework that have many of the same advantages of libusb, but are not portable off the Windows platform.
The last custom device I worked on was based on a Cypress device, and we were able to ship their driver and an associated DLL to make our application code easier to build. I don't know off the cuff if there is any equivalent available for your device.
For a really good overview, I recommend the USB FAQ, and the latest edition of Jan's book, USB Complete.