budman7
There can be a maximium of 4 primary partitions.One of the Primary can be an extended.
Which can contain as many partitions as you desire. No limit, except for the size of the medium.
No difference between ide and scsi as far as number of partitions go.
jens
It's limited cause of the amount of partition devices the kernel can make and use.
Last time I checked:
IDE: Max 63 (4 primary/extended and 59 logical)
SCSI: Max 11 or 27
borromini
Do not take this as Windows bashing, but Windows can only make 26 partitions normally (letters of the alphabet). That would imply not using any floppy, cd-rom or other device.
sf433
I found from text book, It was printed a few years ago. I am not sure it is absolutly correct.
max of partittion for ide = 63
max of partition for scsi = 15
a) but I don't know how to calculate,
For each hd, let say hda, max of partition are
hda1-primary
hda2-primary
hda3-primary
hda4-extended
hda5-logical
hda6-logical
hda7-logical
hda8-logical
total: max 8 partitions per each hd
if max of hd is 8, it should be 8x8= 64 partitions, why there is only 63? where is the other one?
b) scsi is only 15 ? only 2 scsi(how could it be)? 2x8= 16 partitions? where is the other one?
c) It looks like a simple question, but I really want to get a right concept from basic again.
budman7
I think you are getting the hard drives and partitions mixed up. 63 ide hard drives(that is a lot of controllers) and 15 scsi. I believe you can chain 127 usb devices together, making them all hard drives.I personally have 10 partitions on my120 GB hard drive.
Off topic
Quote:
Do not take this as Windows bashing, but Windows can only make 26 partitions normally (letters of the alphabet). That would imply not using any floppy, cd-rom or other device.Actually Windows can only make 23 partitions. One primary and one extended that can have 22 logical
C: is primary
A: is dedicated to floppy
B: is dedicated to floppy(how stupid is that)
D: would be the extended that holds all the logical
jens
Originally written by sf433
why there is only 63
Cause 63 is simply the the maximum amount of partition devices the kernel can make on an IDE drive and use. Their's no other reason (in Linux the firts 4 are reserved for primary/extended, leaving maximum 59 partitions as logical).
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khakisheep
Need to clarify something. On another forum I'm encountering some people saying that with Linux it can only handle and or create and manage a maximum of 63 partitions? I am having trouble grasping this mystical '63' number I keep seeing. Can anyone here confirm this and explain it? And is there a workaround. I've always known and believed I could create as many logical partitions as I wanted, maxing at like 255 or something. Is this a Linux exclusive situation or what?
Users at other forum weren't too helpful with this matter, they basicly said try to push past 63 and see what happens. Well in a perfect world I could, but I have a deadline for this project at work and cannot get to 63 and then have my project flounder and die. I need work-arounds, confirmations etc, if anyone can. Many thanks ahead of time.
Someone mentioned creating individual kernel modules as a workaround to creating hundreds of partitions for my project. Can anyone shed light on this as well.
jobeard
the answer is likely to be in the size of the programming structure that holds the memory copy of the actual partition table.remember, each physical HD has one partition table holding all the mappings for that HD.this will result in a hierarchy of HD[x]->part[y]->filesys-info
such limits are ususally powers of 2, so expect 32,64,128, ...
If you have access to Lunix source, you can find the answer there.
jobeard
Linux manpage 8 fdisk clearly states
IDE max 63, SCSI max 15,
see also /usr/src/linux/Documentation/devices.txt
Mictlantecuhtli
Taken from Linux kernel documentation (not sure how up to date it is):
3 block First MFM, RLL and IDE hard disk/CD-ROM interface
0 = /dev/hda Master: whole disk (or CD-ROM)
64 = /dev/hdb Slave: whole disk (or CD-ROM)
For partitions, add to the whole disk device number:
0 = /dev/hd? Whole disk
1 = /dev/hd?1 First partition
2 = /dev/hd?2 Second partition
...
63 = /dev/hd?63 63rd partition
For Linux/i386, partitions 1-4 are the primary partitions, and 5 and above are logical partitions.
Other versions of Linux use partitioning schemes appropriate to their respective architectures.
The documentation also includes only ten IDE hard disk / CD-ROM interfaces, so the devices would go from hda to hdt only (master & slave).
tdeg
I guess the big question is why do you need more than 63 partitions?
Can't you just use a few partitions and then different mount points?
Are you trying to have a computer with every type of possible filesystem or something?
khakisheep
I suppose I could have just a few partitions and then different mount points...but again, this is my first experience with Linux. And my reason for coming to these forums was to get advice on how to go about this task and learn from people who may already know how to do what I'm attempting to do. So again, my task is a SINGLE HDD with the possibility of installing/booting an individual set of software drivers for 150+ motherboards.
They cannot annoy and touch one another, my only thoughts were seperate partitions with seperate installations of an OS.
I don't care how its done, or what methods I have to use. For ease on our technicians I'm trying to accomplish this with windows but not having any luck. Linux seems to be offering me the solutions I need but straight answers are what I'm needing but aren't receiving. I'm attempting to research all suggestions that you guys mention, but for a noob its proving difficult at best to answer questions of why I don't try this, when its not an option I ever knew existed.
If you have a suggestion PLEASE by all means continue to post them.
Examples are nice! Here's something that might work, you may want to read about this and try this. etc. etc.
nodsu
How about some virtual machine solution like VMWare or xen?
Or mounting files (loop device) as / for different incarnations of Linux at boot?
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