Does Grub have an OS or drivers of its own?
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I've been reading the Grub intro from Dedoimedo and despite being an excellent guide it raised some more questions:
Does Grub rely on any OS in its implementation? I know it's possible to configure it to load Windows, Linux, FreeBSD, etc. So I'm guessing it doesn't rely on any kernel (even a special-made minimal Linux kernel) right? In that case, how can it show a graphical interface, access whatever media to load the kernel, etc. all in "20-30 KB of binary"?
Update: one follow up question: what are all those vmlinuz files in the /boot dir? Are those in any way related to Grub?
grub
edited 1 min ago
Rui F Ribeiro
37.3k1374118
asked Mar 31 '17 at 8:14
AlexStack
3562510
add a comment |Â
up vote
0
down vote
favorite
I've been reading the Grub intro from Dedoimedo and despite being an excellent guide it raised some more questions:
Does Grub rely on any OS in its implementation? I know it's possible to configure it to load Windows, Linux, FreeBSD, etc. So I'm guessing it doesn't rely on any kernel (even a special-made minimal Linux kernel) right? In that case, how can it show a graphical interface, access whatever media to load the kernel, etc. all in "20-30 KB of binary"?
Update: one follow up question: what are all those vmlinuz files in the /boot dir? Are those in any way related to Grub?
grub
edited 1 min ago
Rui F Ribeiro
37.3k1374118
asked Mar 31 '17 at 8:14
AlexStack
3562510
add a comment |Â
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I've been reading the Grub intro from Dedoimedo and despite being an excellent guide it raised some more questions:
Does Grub rely on any OS in its implementation? I know it's possible to configure it to load Windows, Linux, FreeBSD, etc. So I'm guessing it doesn't rely on any kernel (even a special-made minimal Linux kernel) right? In that case, how can it show a graphical interface, access whatever media to load the kernel, etc. all in "20-30 KB of binary"?
Update: one follow up question: what are all those vmlinuz files in the /boot dir? Are those in any way related to Grub?
grub
edited 1 min ago
Rui F Ribeiro
37.3k1374118
asked Mar 31 '17 at 8:14
AlexStack
3562510
I've been reading the Grub intro from Dedoimedo and despite being an excellent guide it raised some more questions:
Does Grub rely on any OS in its implementation? I know it's possible to configure it to load Windows, Linux, FreeBSD, etc. So I'm guessing it doesn't rely on any kernel (even a special-made minimal Linux kernel) right? In that case, how can it show a graphical interface, access whatever media to load the kernel, etc. all in "20-30 KB of binary"?
Update: one follow up question: what are all those vmlinuz files in the /boot dir? Are those in any way related to Grub?
grub
grub
edited 1 min ago
Rui F Ribeiro
37.3k1374118
asked Mar 31 '17 at 8:14
AlexStack
3562510
edited 1 min ago
Rui F Ribeiro
37.3k1374118
asked Mar 31 '17 at 8:14
AlexStack
3562510
edited 1 min ago
Rui F Ribeiro
37.3k1374118
edited 1 min ago
Rui F Ribeiro
37.3k1374118
edited 1 min ago
Rui F Ribeiro
37.3k1374118
37.3k1374118
asked Mar 31 '17 at 8:14
AlexStack
3562510
asked Mar 31 '17 at 8:14
AlexStack
3562510
asked Mar 31 '17 at 8:14
AlexStack
3562510
3562510
add a comment |Â
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
2
down vote
accepted
Right, Grub is standalone and implements all its own drivers. It does take rather more than “20-30 KB of binary†to do this though; my /boot/grub/i386-pc directory contains 2.4 MiB’s worth of modules (which is where all the Grub features are implemented).
The vmlinuz files in /boot are the various Linux kernels you have installed. Grub doesn’t need them, they’re what Grub loads to boot Linux (along with an initramfs).
answered Mar 31 '17 at 8:18
Stephen Kitt
152k23338406
Good to know. I'm curious what are the vmlinuz images in /boot? Added it as an "Update" question to the original question so feel free to edit the answer if you see fit :)
– AlexStack
Mar 31 '17 at 9:31
Really all drivers? I don't know much about Grub, but I've been writing a bootloader for an embedded device as fast and compactubootreplacement. Of course I had to write some drivers, but not all, as there was some bootROM code executed by the CPU first, doing things like initializing the memory where my bootloader lives. I can imagine that Grub also relies on those lowest-level drivers, implemented in the BIOS or UEFI or whatever may be up to date in today's PCs.
– Philippos
Mar 31 '17 at 11:54
I meant in opposition to using Linux drivers (or something else). The Grub drivers do use the BIOS in some cases; for examplebiosdisk.cuses the BIOS to access disks, but there’s alsopata.cto directly access PATA disks (allowing Grub to access drives which the BIOS can’t — which was useful on many older systems).
– Stephen Kitt
Mar 31 '17 at 11:59
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
accepted
Right, Grub is standalone and implements all its own drivers. It does take rather more than “20-30 KB of binary†to do this though; my /boot/grub/i386-pc directory contains 2.4 MiB’s worth of modules (which is where all the Grub features are implemented).
The vmlinuz files in /boot are the various Linux kernels you have installed. Grub doesn’t need them, they’re what Grub loads to boot Linux (along with an initramfs).
answered Mar 31 '17 at 8:18
Stephen Kitt
152k23338406
Good to know. I'm curious what are the vmlinuz images in /boot? Added it as an "Update" question to the original question so feel free to edit the answer if you see fit :)
– AlexStack
Mar 31 '17 at 9:31
Really all drivers? I don't know much about Grub, but I've been writing a bootloader for an embedded device as fast and compactubootreplacement. Of course I had to write some drivers, but not all, as there was some bootROM code executed by the CPU first, doing things like initializing the memory where my bootloader lives. I can imagine that Grub also relies on those lowest-level drivers, implemented in the BIOS or UEFI or whatever may be up to date in today's PCs.
– Philippos
Mar 31 '17 at 11:54
I meant in opposition to using Linux drivers (or something else). The Grub drivers do use the BIOS in some cases; for examplebiosdisk.cuses the BIOS to access disks, but there’s alsopata.cto directly access PATA disks (allowing Grub to access drives which the BIOS can’t — which was useful on many older systems).
– Stephen Kitt
Mar 31 '17 at 11:59
add a comment |Â
up vote
2
down vote
accepted
Right, Grub is standalone and implements all its own drivers. It does take rather more than “20-30 KB of binary†to do this though; my /boot/grub/i386-pc directory contains 2.4 MiB’s worth of modules (which is where all the Grub features are implemented).
The vmlinuz files in /boot are the various Linux kernels you have installed. Grub doesn’t need them, they’re what Grub loads to boot Linux (along with an initramfs).
answered Mar 31 '17 at 8:18
Stephen Kitt
152k23338406
Good to know. I'm curious what are the vmlinuz images in /boot? Added it as an "Update" question to the original question so feel free to edit the answer if you see fit :)
– AlexStack
Mar 31 '17 at 9:31
Really all drivers? I don't know much about Grub, but I've been writing a bootloader for an embedded device as fast and compactubootreplacement. Of course I had to write some drivers, but not all, as there was some bootROM code executed by the CPU first, doing things like initializing the memory where my bootloader lives. I can imagine that Grub also relies on those lowest-level drivers, implemented in the BIOS or UEFI or whatever may be up to date in today's PCs.
– Philippos
Mar 31 '17 at 11:54
I meant in opposition to using Linux drivers (or something else). The Grub drivers do use the BIOS in some cases; for examplebiosdisk.cuses the BIOS to access disks, but there’s alsopata.cto directly access PATA disks (allowing Grub to access drives which the BIOS can’t — which was useful on many older systems).
– Stephen Kitt
Mar 31 '17 at 11:59
add a comment |Â
up vote
2
down vote
accepted
up vote
2
down vote
accepted
Right, Grub is standalone and implements all its own drivers. It does take rather more than “20-30 KB of binary†to do this though; my /boot/grub/i386-pc directory contains 2.4 MiB’s worth of modules (which is where all the Grub features are implemented).
The vmlinuz files in /boot are the various Linux kernels you have installed. Grub doesn’t need them, they’re what Grub loads to boot Linux (along with an initramfs).
answered Mar 31 '17 at 8:18
Stephen Kitt
152k23338406
Right, Grub is standalone and implements all its own drivers. It does take rather more than “20-30 KB of binary†to do this though; my /boot/grub/i386-pc directory contains 2.4 MiB’s worth of modules (which is where all the Grub features are implemented).
The vmlinuz files in /boot are the various Linux kernels you have installed. Grub doesn’t need them, they’re what Grub loads to boot Linux (along with an initramfs).
answered Mar 31 '17 at 8:18
Stephen Kitt
152k23338406
edited Mar 31 '17 at 9:47
answered Mar 31 '17 at 8:18
Stephen Kitt
152k23338406
answered Mar 31 '17 at 8:18
Stephen Kitt
152k23338406
answered Mar 31 '17 at 8:18
Stephen Kitt
152k23338406
152k23338406
Good to know. I'm curious what are the vmlinuz images in /boot? Added it as an "Update" question to the original question so feel free to edit the answer if you see fit :)
– AlexStack
Mar 31 '17 at 9:31
Really all drivers? I don't know much about Grub, but I've been writing a bootloader for an embedded device as fast and compactubootreplacement. Of course I had to write some drivers, but not all, as there was some bootROM code executed by the CPU first, doing things like initializing the memory where my bootloader lives. I can imagine that Grub also relies on those lowest-level drivers, implemented in the BIOS or UEFI or whatever may be up to date in today's PCs.
– Philippos
Mar 31 '17 at 11:54
I meant in opposition to using Linux drivers (or something else). The Grub drivers do use the BIOS in some cases; for examplebiosdisk.cuses the BIOS to access disks, but there’s alsopata.cto directly access PATA disks (allowing Grub to access drives which the BIOS can’t — which was useful on many older systems).
– Stephen Kitt
Mar 31 '17 at 11:59
add a comment |Â
Good to know. I'm curious what are the vmlinuz images in /boot? Added it as an "Update" question to the original question so feel free to edit the answer if you see fit :)
– AlexStack
Mar 31 '17 at 9:31
Really all drivers? I don't know much about Grub, but I've been writing a bootloader for an embedded device as fast and compactubootreplacement. Of course I had to write some drivers, but not all, as there was some bootROM code executed by the CPU first, doing things like initializing the memory where my bootloader lives. I can imagine that Grub also relies on those lowest-level drivers, implemented in the BIOS or UEFI or whatever may be up to date in today's PCs.
– Philippos
Mar 31 '17 at 11:54
I meant in opposition to using Linux drivers (or something else). The Grub drivers do use the BIOS in some cases; for examplebiosdisk.cuses the BIOS to access disks, but there’s alsopata.cto directly access PATA disks (allowing Grub to access drives which the BIOS can’t — which was useful on many older systems).
– Stephen Kitt
Mar 31 '17 at 11:59
Good to know. I'm curious what are the vmlinuz images in /boot? Added it as an "Update" question to the original question so feel free to edit the answer if you see fit :)
– AlexStack
Mar 31 '17 at 9:31
Good to know. I'm curious what are the vmlinuz images in /boot? Added it as an "Update" question to the original question so feel free to edit the answer if you see fit :)
– AlexStack
Mar 31 '17 at 9:31
Really all drivers? I don't know much about Grub, but I've been writing a bootloader for an embedded device as fast and compact
uboot replacement. Of course I had to write some drivers, but not all, as there was some bootROM code executed by the CPU first, doing things like initializing the memory where my bootloader lives. I can imagine that Grub also relies on those lowest-level drivers, implemented in the BIOS or UEFI or whatever may be up to date in today's PCs.– Philippos
Mar 31 '17 at 11:54
Really all drivers? I don't know much about Grub, but I've been writing a bootloader for an embedded device as fast and compact
uboot replacement. Of course I had to write some drivers, but not all, as there was some bootROM code executed by the CPU first, doing things like initializing the memory where my bootloader lives. I can imagine that Grub also relies on those lowest-level drivers, implemented in the BIOS or UEFI or whatever may be up to date in today's PCs.– Philippos
Mar 31 '17 at 11:54
I meant in opposition to using Linux drivers (or something else). The Grub drivers do use the BIOS in some cases; for example
biosdisk.c uses the BIOS to access disks, but there’s also pata.c to directly access PATA disks (allowing Grub to access drives which the BIOS can’t — which was useful on many older systems).– Stephen Kitt
Mar 31 '17 at 11:59
I meant in opposition to using Linux drivers (or something else). The Grub drivers do use the BIOS in some cases; for example
biosdisk.c uses the BIOS to access disks, but there’s also pata.c to directly access PATA disks (allowing Grub to access drives which the BIOS can’t — which was useful on many older systems).– Stephen Kitt
Mar 31 '17 at 11:59
add a comment |Â
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