Liam_on_Linux (![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
liam_on_linux) wrote2013-10-22 08:13 pm
liam_on_linux) wrote2013-10-22 08:13 pm
Entry tags:
- bios,
- dos,
- flash,
- floppies,
- memory key,
- rant,
- thumb drive,
- usb,
- whine
Why I prefer to use optical media to USB thumbdrives for OS installations
Not only do I have recent, decent-performance, still-perfectly-usable PC hardware that can't boot off USB, or can but can't remember the setting* so that it has to be done every time you need it, but I also note that the BIOS in the current shipping versions of both VirtualBox and VMware cannot boot from USB devices.
It is not a rare or uncommon problem.
Yes, I have had dozens of techies say they've never seen it. Well, tough. It's not rare; it just means that they've had a lot less breadth of experience than I have.
-----
* Some BIOSes "see" a USB key as a hard disk. You can place it at the top of the boot order, but if you reboot the machine without the key present, the BIOS sees that that specific disk device has disappeared and removes it from the boot device list. This also means that every different USB key comes up as a different device meaning that it is impossible to set the BIOS to boot from USB first, then rotating media.
Also, some BIOSes offer a choice of USB HD, USB FD or USB CD - all as different, mutually-incompatible devices. Go on then, which is a memory stick - a virtual hard disk, virtual floppy disk or a virtual optical disk?
Hint: it depends on the partitioning, not the hardware.
Floppies aren't partitioned; the BIOS has to look for a boot sector at the start of the media.
Hard disks are partitioned (except in RAIDs, sometimes), so the BIOS needs to look for the master boot record, find the bootable partition, locate that, find its boot sector and then load that.
Optical drives, including fake ones, are ISO9660 filesystems or a variant thereof, which means a 3rd method. Except rewritables, which could be UFS, meaning universal filesystem not Unix File System as that TLA means under BSD-like OSes.
Oh, yes, and on some manufacturers' kit, *their own-brand USB removable drives* appear as system-integrated (e.g. PATA/SATA) ones to the BIOS, whereas generic USB removable drives don't and are seen as USB devices. IBM/Lenovo are good at this, but it's not unknown on HP, Dell and other kit. Install a Lenovo USB floppy drive on a Lenovo notebook, the BIOS makes it appear to be on the floppy controller. Put the same drive on a Toshiba, it doesn't work; put a Toshiba drive on the Lenovo, it works fine but as a USB drive and although MS-DOS boots, it then can't see the floppy drive it booted from and your BIOS reflash fails.
Getting the impression that I've fought a lot of battles with bootable USB media yet?
I've fought a lot of battles with bootable USB devices.
Including with the PLOP boot manager, which on some PCs, can only access certain USB ports and not others.
There's a reason I like CDRs and DVDRs. They're cheap and they generally just work and anything younger than a Pentium II can usually boot off them.
It is not a rare or uncommon problem.
Yes, I have had dozens of techies say they've never seen it. Well, tough. It's not rare; it just means that they've had a lot less breadth of experience than I have.
-----
* Some BIOSes "see" a USB key as a hard disk. You can place it at the top of the boot order, but if you reboot the machine without the key present, the BIOS sees that that specific disk device has disappeared and removes it from the boot device list. This also means that every different USB key comes up as a different device meaning that it is impossible to set the BIOS to boot from USB first, then rotating media.
Also, some BIOSes offer a choice of USB HD, USB FD or USB CD - all as different, mutually-incompatible devices. Go on then, which is a memory stick - a virtual hard disk, virtual floppy disk or a virtual optical disk?
Hint: it depends on the partitioning, not the hardware.
Floppies aren't partitioned; the BIOS has to look for a boot sector at the start of the media.
Hard disks are partitioned (except in RAIDs, sometimes), so the BIOS needs to look for the master boot record, find the bootable partition, locate that, find its boot sector and then load that.
Optical drives, including fake ones, are ISO9660 filesystems or a variant thereof, which means a 3rd method. Except rewritables, which could be UFS, meaning universal filesystem not Unix File System as that TLA means under BSD-like OSes.
Oh, yes, and on some manufacturers' kit, *their own-brand USB removable drives* appear as system-integrated (e.g. PATA/SATA) ones to the BIOS, whereas generic USB removable drives don't and are seen as USB devices. IBM/Lenovo are good at this, but it's not unknown on HP, Dell and other kit. Install a Lenovo USB floppy drive on a Lenovo notebook, the BIOS makes it appear to be on the floppy controller. Put the same drive on a Toshiba, it doesn't work; put a Toshiba drive on the Lenovo, it works fine but as a USB drive and although MS-DOS boots, it then can't see the floppy drive it booted from and your BIOS reflash fails.
Getting the impression that I've fought a lot of battles with bootable USB media yet?
I've fought a lot of battles with bootable USB devices.
Including with the PLOP boot manager, which on some PCs, can only access certain USB ports and not others.
There's a reason I like CDRs and DVDRs. They're cheap and they generally just work and anything younger than a Pentium II can usually boot off them.