OSINBMG - BOOT MANAGER INFORMATION AND OVERVIEW 01/26/96 ======================================================================= Boot Manager Information and Overview--All OS/2 Releases ======================================================================= Please Read Entire Document for Full Explanation of Procedures -------------------------------------------------------------- DESCRIPTION This document provides information about the Boot Manager. RESOLUTION An Overview of the Boot Manager ------------------------------- If you are going to install multiple operating systems, you can use the Boot Manager feature to manage selective-startup systems. From the Boot Manager startup menu, you can select which operating system you want to use each time you start your system. Use the FDISK utility program during the installation of OS/2 to install the Boot Manager feature. FDISK is provided with OS/2 and can be used to manage such tasks as creating and deleting the partitions on your hard disk. Partitions are divisions you create on your hard disk to use as separate storage areas. The following is a brief list of the steps you perform to set up your hard disk for multiple operating systems. * Install Boot Manager in its own partition (1 MB in size) * Create partitions for any operating systems (including OS/2) * Install other operating systems in partitions created for them. If you want OS/2 to work with DOS and Windows, you must install DOS and Windows first. Otherwise, most other operating systems can be installed after installing OS/2. * Install the OS/2 operating system Hard-Disk Management -------------------- A hard disk can be partitioned in several different ways. For example, your hard disk can have one partition that takes up the entire hard disk. However, if you are going to install multiple operating systems on your hard disk (with Boot Manager), you MUST separate the hard disk into multiple partitions. During installation of OS/2 2.x, or when using the Advanced Installation method for OS/2 Warp, you are asked how you want your partitions set up. The default choice is to set up one partition (if you are installing on a hard disk with NO DATA) or to preserve the setup of an existing hard disk. If you choose to specify your own partition, the FDISK screen is displayed. From the FDISK screen, you specify the number and type of partitions that you want created. You can create primary partitions, which are used typically for operating systems. You also can create logical drives in an area of the hard disk that is outside the primary partitions. This area is known as the extended partition. The logical drives within the extended partition are used typically to hold programs and data. Note: If a partition is going to contain an operating system, the system must be within the first 1024 cylinders. Your hard disk can be separated into a maximum of 4 partitions. You can have 4 primary partitions or 3 primary partitions, and the extended partition. If you are going to install multiple operating systems on your hard disk, you must create one primary partition to contain the programs that manage the startup of the multiple operating systems. This partition is referred to as the Boot Manager partition. After the Boot Manager partition is created, you can create up to 3 additional primary partitions (to hold 3 operating systems), as in the following example: Boot Manager ______________________ DOS 5.0 ______________________ DOS 6.1 ______________________ OS/2 Warp An important aspect of primary partitions is that, at any given moment, only one of the primary partitions is active.When a given primary partition is active, any other primary partitions on the same physical disk cannot be accessed. Therefore, the operating system in one primary partition cannot access data in another primary partition on the same physical disk. Another way of subdividing your hard disk is to create logical drives within an extended partition. Typically, logical drives are used to hold programs and data. However, you also can install OS/2 Warp in a logical drive, as in the following example: Boot Manager | = Primary Partition _____________| DOS 5.0 | = Primary Partition _____________| OS/2 2.1 | = Primary Partition _____________| OS/2 Warp | = Logical Drive | _____________| | DATA | | _____________| = Logical Drive | = Extended Partition DATA | | _____________| = Logical Drive | The extended partition takes the place of one of the primary partitions on your hard disk. In other words, if you create logical drives within an extended partition, your hard disk can contain only 3 primary partitions. Note: You MUST have one primary partition in addition to the Boot Manager partition. In the preceding example, notice that 2 logical drives have been set aside for data. That data can be shared by all operating systems (provided the file-system formats of the logical drives are compatible with the operating systems). All of the logical drives exist within one partition: the extended partition. You don't explicitly create the extended partition. It is created the first time you create a logical (non-primary) drive. One of the differences between a logical drive and a primary partition is that each logical drive is assigned a unique drive letter. However, all primary partitions on a hard disk share the same drive letter. (On the first hard disk in your system, the primary partitions share drive C). This means that only one primary partition at a time can be accessed on a hard disk. Note: The Boot Manager partition is different from other primary partitions, because it is never assigned a drive letter. If you want OS/2 Warp to be able to access the data in the partition of another operating system (for example, the DOS partition), install OS/2 Warp in a logical drive, as in the following example. Primary (Boot Manager) | = No Drive Letter _______________________|______ Primary (DOS 5.0) | | | | _______________________| |= These partitions share C: Primary (DOS 6.1) | | (Only one can be active) _______________________|______| Logical Drv (OS/2 Warp)| _______________________| = D: Logical Drive (Data) | _______________________| = E: Logical Drive (Data) | _______________________| = F: Notice the drive letter assignments in this example. The operating system that is active when you start the system, performs a process known as drive mapping, where partitions and logical drives are assigned drive letters. All of the primary partitions are mapped first, and logical drives within extended partitions are assigned subsequent drive letters (up through Z). Important: Only one primary partition per hard disk can be active at a time. So, only one primary partition is actually assigned the letter "C" at any one time. The other primary partitions are not mapped. An operating system maps only those drives with a format type that it supports. For example, DOS does not support the installable file system (IFS) format, such as the High Performance File System. Therefore, any partition or logical drive that is formatted with IFS is not mapped by DOS and is not assigned a drive letter. ______________________________________________________________________ IBM disclaims all warranties, whether express or implied, including without limitation, warranties of fitness and merchantability with respect to the information in this document. By furnishing this document, IBM grants no licenses to any related patents or copyrights. Copyright (c) 1994, 1996 IBM Corporation. Any trademarks and product or brand names referenced in this document are the property of their respective owners. Consult your product manuals for complete trademark information.