Get PC BIOS back on UEFI only system(github.com) |
Get PC BIOS back on UEFI only system(github.com) |
I would really love to know more about this.
I assume it's this VGA driver:
https://github.com/tongzx/nt5src/tree/master/Source/XPSP1/NT...
> It is based on the SpiderSTREAMS source, stremul\msgsrvr.c.
There's some special history.
Could this be seen a distribution by Microsoft? I mean, if you can sue Pirate Bay for the content they host...
and VESA VBIOS from SeaBIOS project
Unfortunately I believe modern GPUs without a standard VBIOS may not act enough like an IBM VGA for a generic VGA VBIOS to work, so I see another project for someone in the future: a retrofit VBIOS, especially for those GPUs e.g. Intel's for which lots of open-source driver code and documentation is available but later models no longer come with a VBIOS.
Perhaps also injecting a true CSM from an old closed-source UEFI BIOS, before they started removing it, is worth doing as in my limited experience SeaBIOS isn't as quite compatible as the closed-source ones for some edge-cases.
But, as okanat says, if the goal is to run legacy operating systems, then modern hardware is going to be challenging in other ways too. IME the biggest thing I want PC BIOS back for is the ability to use non-GPT disk layouts, which this doesn't accomplish as, as to use it you put it on the EFI partition on your GPT disk.
Meanwhile, other implementations will not consider the disk bootable in BIOS mode if the partition in the pMBR is not marked bootable.
For instance, whole-disk btrfs. Or old BSD partition schemes.
In any case that is far beyond the original scope of booting old PC OSes, which MBR support alone serves really well (99.9% of the way there, really), which is why I assumed by default you were thinking of MBR, not some other weird scheme.
This is the project that I think has been needed for a while now.
So much that a Replacement CSM for user implementation has been top of mind to suggest here, awaiting the next time I see a request from programmers looking for a worthwhile project.
Now there's nothing more performant than a request being granted before it's even been made :)
Additionally, it was just 3 years ago that memtest86plus finally got a UEFI version. That was painful for a few years there. (Though the 4GB RAM limit would have made this not an ideal solution.)
I'm sure there are other such self-hosting utilities that haven't been and may not be ported/rewritten to work under UEFI.
For stuff that needs to be bootable by both BIOS and UEFI the only portable solution is to use MBR, not GPT. That means all legacy BIOS systems will boot it, and so will all UEFI systems since UEFI must support MBR.
For ISOs that need to additionally be booted off of optical media (aka ISOHYBRIDs) the story gets more complicated, but ultimately what you need to take away from that is the same: avoid GPT at all cost.
Seems like an inconsistency which could be addressed by adding it to the spec and/or test suite.
I guess the other thing I don’t know, is whether there is any actual real world pressure on firmware vendors to pass the test suite.
MBR is two things with the same name. It is both the format of the storage device and describes a booting mode using a master boot record and up to 4 partitions.
GPT is one thing. It is a format for a storage device. It is the alternative to the MBR format for storage devices. It has nothing to do with (U)EFI.
BIOS or BIOS/csm are not types of formats for storage devices. They are types of boot processes. (U)EFI is another type of boot process.
You can easily mix and match boot types (BIOS/csm vs UEFI) and storage device format types (GPT vs MBR). As others have said, there may be some slight incompatibilities on some rare hardware/software configs, but mostly it just works.
I invite you to read what I said again.
I am not sure what I said that was incorrect though. As I'm always looking to learn, which bit? I am currently assuming the 'rest' about GPT on true BIOS machines. I suppose I have never booted off GPT formatted disks in true BIOS machines. I always boot off MBR formatted disks and just used the GPT as storage/etc.
But I'm unclear on how this would break things since you can still have the MBR in the first sector on a GPT formatted disk. And how could the true BIOS motherboards detect GPT format on the disks when they don't know about it?
While the space wasted by GPT and partitions and by the arbitrary alignment rules used by various formatting tools is not great, I do not see any reason why it should exist. The space wasted now with GPT and UEFI is several orders of magnitude greater than it was with traditional partition tables, so eliminating it has become more attractive.
Such SSDs and HDDs are not bootable, but for me this is a desirable feature, not a bug. I boot my computers either from Ethernet (e.g. most of my servers) or from a removable USB memory.
The SSDs and HDDs with a whole-disk file system are also wholly encrypted. As in a proper encryption implementation, there is complete separation between the encrypted data and the encryption key. The encrypted disks or their hosting computers do not contain any information about decryption, unlike in many systems of disk encryption. The encrypted decryption keys can be found only on external or remote boot media, which are not normally associated with the hosting computers.
I wouldn't recommend that. It makes the disk appear to be empty to many tools (and possibly some operating systems), which could lead to data loss. That's the reason GPT has the protective MBR: it makes the disk appear to be full to legacy tools which don't understand the GPT format.
Windows frequently overwrites any bootable Linux drive, so it might have even less restraints with an apparently empty drive that does not have GPT structure.
Because of the risk of Windows messing with them, I also do not insert any of my bootable USB memories in a live Windows computer, even when they have GPT structure. For data interchange with Windows, I use only clean and non-bootable exFAT formatted USB memories.
I am not the OP and I do not do this. However...
Yes, the disk space used is a rounding error and one far right of the decimal point.
But there is extra space used in the human brain that sets this up.
Instead of `/dev/sda1` it's `/dev/sda`. Instead of `/dev/nvme0l0p1` or whatever (I own almost no NVMe kit) it's `/dev/nvme0l0`. And so on.
This could be helpful; I can certainly imagine it simplifying things somewhat.
Ideally, BIOS/CSM systems should not care about what type of partition table format a disk uses, and just boot by loading the boot sector (the 1st sector), and passing control to it.
In the real world, some machines will check for whether an MBR exists (by MBR meaning the partition table contained in the first sector, also called "msdos" partition table, naming varies depending on who you ask), some of them will check whether there is any partition set as active in said MBR, some of them will, indeed, check if there is a GPT (past any protective MBR), and ignore such disks - possibly because firmware writers thought that no GPT disk should be bootable on BIOS systems (Windows doesn't support it, so...), to avoid passing control to an empty protective MBR and possibly crash or hang as a result.
If it were an Oracle source code leak, I expect they’d have a crack team of lawyers suing people 24x7 until it was all gone… maybe that’s why there haven’t (to my knowledge) been any Oracle source code leaks (I vaguely remember one of Solaris, but that wasn’t such a clearcut case since IIRC it was mostly previously open sourced code)
Well, it wouldn’t surprise me if some unfriendly intelligence agency somewhere had succeeded in stealing some of it, but if they have, they are unlikely to release it publicly
During the mid-90s, the Unix Wars were raging and Unix System Labs was suing U.C. Berkeley over the intellectual property of Unix source code. Unix had been written at AT&T Bell Labs, but Berkeley had licensed and forked their own, based on improved networking code, and by this time it was ready to run on i386 systems. In fact, USL had borrowed back some BSD code, allegedly without crediting them. Berkeley had been busy removing AT&T code and replacing it, so they could relicense BSD Unix.
USL, part of AT&T (but later purchased by Novell), contended that Berkeley could not easily make a "clean room implementation" of any kernel code or device drivers, if those programmers had read or worked with original AT&T source code. They told the courts (and journalists) that the programmers might be tempted to reproduce proprietary Unix code, consciously or subconsciously, and therefore, these programmers were permanently "Mentally Contaminated" and Berkeley should not be allowed to continue distributing BSD [BSDi] Unix.
https://en.wikipedia.org/wiki/UNIX_System_Laboratories,_Inc.....
So when I attended Usenix LISA in 1994, this 3-year lawsuit was at a fever pitch, and someone on the convention floor had manufactured large buttons for attendees to wear, proudly proclaiming "MENTALLY CONTAMINATED", and all the admins and systems programmers had a good laugh about the absurdity of trying to keep a lid on proprietary source code by policing everyone who's ever seen one of its files.
Even weirder is that GitHub hosts all of the tools for activating (i.e. cracking) modern versions of Windows and Office as well. Microsoft really doesn't care.
- https://en.wikipedia.org/wiki/Shared_Source_Initiative#Overv...
- https://news.microsoft.com/source/2002/02/21/microsoft-annou...
I don’t know the current status of those source code access programs but I believe at least some of them are still in effect. IIRC, to stop the Chinese government from dumping Windows, they had to give them source code access, but I believe they are planning to dump it anyway, they see relying on US proprietary software for their government operations as too big a risk
Anyways, very cool to see.
...of which the tools to disable that invasiveness are also on GitHub, so maybe they just care more about maintaining marketshare.