src/sbin/fdisk/fdisk.8 - diff

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Diff for /src/sbin/fdisk/fdisk.8 between version 1.5 and 1.6

version 1.5, 1994/01/28 20:07:17

version 1.6, 1994/09/23 04:30:13

Line 1

.\" $Id$ -*- nroff -*-

.Dd April 4, 1993

.Dt FDISK 8

.\".Os BSD 4

.\" .Os BSD 4

.Sh NAME

.Nm fdisk

.Nd DOS partition maintenance program

.Sh SYNOPSIS

.Nm

.Op Fl i

.Op Fl aiu

.Op Fl u

.Op Ar device

.Bl -tag -width time

.It Fl i

Initializes sector 0 of the disk.

.It Fl u

Is used for updating (editing) sector 0 of the disk.

.El

.Sh PROLOGUE

In order for the BIOS to boot the kernel,

In order for the BIOS to boot the kernel, certain conventions must be

certain conventions must be adhered to.

adhered to.

Sector 0 of the disk must contain boot code,

Sector 0 of the disk must contain boot code, a partition table, and a

a partition table,

magic number.

and a magic number.

BIOS partitions can be used to break the disk up into several pieces.

The BIOS brings in sector 0

The BIOS brings in sector 0, verifies the magic number, and begins

(does it really use the code?)

executing the code at the first byte.

and verifies the magic number.

This code is turn searches the DOS partition table for an `active'

It then searches the 4 BIOS partitions described by sector 0

partition.

to determine which of them is

If one is found, the boot block from that partition is loaded and replaces

.Em active.

the original boot block.

This boot then brings in the secondary boot block from the

Under DOS, you could have one or more partitions with one active.

.Em active

partition and runs it.

Under DOS,

you could have one or more partitions with one

.Em active.

The DOS

.Nm

program can be used to divide space on the disk into partitions and set one

program can be used to divide space on the disk into partitions and set

.Em active.

one active.

.Sh DESCRIPTION

.Pp

The NetBSD program

.Nm

serves a similar purpose to the DOS program.

When called with no arguments, it prints the sector 0 partition table.

An example follows:

.Bd -literal

******* Working on device /dev/rwd0d *******

parameters extracted from in-core disklabel are:

Line 102 are used to indicate that the partition

Line 89 are used to indicate that the partition

The

.Nm

program will enter a conversational mode.

This mode is designed not to change any data unless you explicitly tell it to.

This mode is designed not to change any data unless you explicitly tell it to;

.Nm

selects defaults for its questions to guarantee the above behavior.

selects defaults for its questions to guarantee that behavior.

.Pp

It displays each partition

It displays each partition and asks if you want to edit it.

and ask if you want to edit it.

If you reply affirmatively,

If you say yes,

it will step through each field showing the old value

and asking for a new one.

When you are done with a partition,

.Nm

will display it and ask if it is correct.

will display the information again and ask if it is correct.

.Nm

will then procede to the next entry.

.Pp

Line 130 After all the partitions are processed,

Line 116 After all the partitions are processed,

you are given the option to change the

.Em active

partition.

To change only the

.Em active

partition, you can use the

.Fl a

flag instead.

.Pp

Finally,

when the all the data for the first sector has been accumulated,

you are asked if you really want to rewrite sector 0.

.Nm

Only if you answer yes,

will ask if you really want to rewrite sector 0.

will the data be written to disk.

Only if you reply affirmatively to this question will

.Nm

write anything to the disk.

.Pp

The difference between the

.Fl u

Line 143 flag and

Line 137 flag and

flag is that

the

.Fl u

flag just edits the fields as they appear on the disk.

flag just edits the fields as they appear on the disk, while the

While the

.Fl i

flag is used to `initialize' sector 0.

The

.Fl i

flag is used to "initialize" sector 0;

flag instructs

it will setup the last BIOS partition to use the whole disk for NetBSD;

.Nm

and make it active.

to start by making the first 3 partitions empty, setting the last partition

to use the whole disk for NetBSD, and marking the last partition active.

.Sh NOTES

.Pp

The automatic calculation of starting cylinder etc. uses

a set of figures that represent what the BIOS thinks is the

geometry of the drive.

These figures are by default taken from the incore disklabel,

These figures are by default taken from the incore disklabel, but

but the program initially gives you an opportunity to change them.

.Nm

gives you an opportunity to change them.

This allows the user to create a bootblock that can work with drives

that use geometry translation under the BIOS.

.Pp

If you hand craft your disk layout,

please make sure that the NetBSD partition starts on a cylinder boundary.

A number of decisions made later may assume this.

(This restriction may be changed in the future.)

(This might not be necessary later.)

.Pp

Editing an existing partition will most likely cause you to

Editing an existing partition is risky, and may cause you to

lose all the data in that partition.

.Pp

You should run this program interactively once or twice to see how it works.

This is completely safe as long as you answer the last question in the negative.

There are subtleties

that the program detects

that are not fully explained in this manual page.

.Sh SEE ALSO

.Xr disklabel 8

.Sh BUGS

One less now, but probably more

There are subtleties that the program detects that are not explained in

this manual page.

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