1Note you will be modifying your HD's if you mess something up here you 2could lose everything on all the drives that you mess with. It is 3therefore advised that you: 4 5 Write down your current configurations. Do this 6 by writing down all partition info (especially their sizes). 7 8 Back up the partitions you are keeping. 9 10If NetBSD has a disk of it's own, you can delay the partitioning until 11the installer requests you to do it. This means that you can safely skip 12the rest of this section. 13 14If NetBSD has to share the disk with another operating system, you must 15take care of partitioning your harddisk before installing NetBSD; creating 16space for at least root, swap and /usr partitions and possibly at 17least one more for /local if you have the space. 18 19Warning: The AHDI partioning function erases all partions on your harddisk 20 even if they are not changed! 21 I know this is rather stupid, but don't say I didn't warn you. 22 23If you want to use an AHDI partitioning sceme and you want to be able to boot 24directly into NetBSD, there are some constraints on the partition layout. 25 26As you might know; every hard disk has a "root sector" that contains 27information about the size of the hard disk and the partitions on the hard 28disk. The root sector can only contain the neccessary data for four 29partitions. Nobody thought that this limitation would cause any problems. 30After all, 640 KByte should be enough. As hard disk grew, it was neccessary 31to define more than four partitions. In order to be more or less compatible 32with the old format, a new type of partition entry was defined: XGM partions. 33 34An XGM partition is a "look over there" sign: Another root sector can be 35found at the start of the XGM partition. This root sector contains the 36remaining real partitions. And this is the big mystery: Partitions defined 37in the root sector of the hard disk are called "primary partitions", 38partitions defined in the root sector of an XGM partition are called 39"extended partitions". 40 41The bootblock will only work if the first NBD partition is a primary 42partition. This is not a limitation of NetBSD but a limitation of TOS/AHDI: 43You can only boot from primary partitions. 44 45If you are creating your partitions with HDX, you'll have to be very careful 46to fulfill this rule. HDX has some very strange ideas when it comes to 47extended partitions. Fortunately, you can edit this stuff: The 48"Edit partition scheme of the unit" dialog box has a button label "expert". 49This button is inactive unless you have defined more than four partitions. 50Click on it *after* you have defined the sizes of the partitions. 51 52A new dialog box appears on the screen. The left side contains two blocks of 53partitions: The upper block always contains the first four partitions, the 54lower block contains the last three partitions. If you have defined less than 557 partitions, some fields of the lower block will contain the string "unused". 56Some of the partitions will be displayed in reverse video: These are the 57extended partitions. 58 59The right side contains six possible ranges for the extended partitions. It 60is not possible to define your own range, you will have to use one of the 61schemes offered by HDX. To quote from Ghostbusters: Choose and die. 62The default scheme used by HDX is the first scheme: Extended partitions start 63with the second partition and end with the second to last partition. If you 64have defined 7 partitions, partitions #2 to #5 will be extended partitions, 65while partitions #1, #6 and #7 will be primary partitions. 66 67You can move the extended partition range by clicking on one of the buttons 68on the right side of the dalog box. Try to find one where your first NetBSD 69partition is a primary partition. Golden rules: 70 * If the disk contains no GEMDOS partitions, don't use AHDI. Let NetBSD 71 handle it alone. 72 * If the disk contains one GEMDOS partition, make it partition #1 and 73 start the extended partition range at partition #3. This allows you 74 to boot from both the GEMDOS and the NetBSD partitions. 75 * If the disk contains two GEMDOS partitions, use partitions #1 and #2 76 for GEMDOS, partition #3 for NetBSD-root. Start the extended partition 77 range with partition #4. 78 * If your disks contains three or more GEMDOS partitions, you are in 79 trouble. Try using partitions #1 and #2 as the first two GEMDOS 80 partitions. Use partition #3 as the first NetBSD partition. Start the 81 extended partition range with partition #4. Put the other NetBSD 82 extended partition range. 83 84Good luck, you'll need it... 85 86