Partition Resizer v. 1.3.0 ========================== (c) Zeleps 1994-98 ================== Program's Manual and Technical Information This file contains important information about the working and usage of Partition Resizer. Please read it carefully before using Partition Resizer. You MUST read README.1ST before running Partition Resizer. DISCLAIMER: This program is freeware. You may freely copy it and distribute it,as long as it remains unchanged and it is distributed with its original documents files. The author is not responsible for any consequence of the use or missuse of this program. Using this program is completely at your own responsibility. 1- What is Partition Resizer 1.1 Why you need Partition Resizer 1.2 How does it work? 1.3 Is it safe? 1.4 Changes made to the previous version 2- Working with Partition Resizer 2.1 Safety precautions 2.2 Running the program: What does what 3- Technical matters 3.1 The partition system 3.2 The DOS (FAT16 and FAT12 only) filesystem structure 3.3 The Windows FAT32 filesystem structure 4- Partitioning Techniques 4.1 Deciding what you want 4.2 Merging many small partitions into a larger one 4.3 Splitting a partition in two 4.4 Playing with partitions' sizes and positions 5- Credits and addresses -------||------- 0- A short note from the author It's been two years since the last release of Partition Resizer (v.1.1.2). Many of you probably lost my traces, since my e-mail address expired and I didn't continue my subscription (one of the reasons for that was the annoyingly large flow of Partition Resizer related e-mails), and I had to leave my home address for a certain period of time (I suppose I lost some correspondance concerning Partition Resizer because of that). Due to lack of time, I didn't really had the opportunity to upgrade the program all this time. But now that FAT32 is out there, I felt it was necessary to make the effort and produce the long awaited new version. So, here it is, Partition Resizer at its best, no known bugs (3 years of feedback was more than enough), full FAT32 support, updated documentation (not much really, but I did my best), and as always, free for everyone to use and enjoy! Please note that, from this point over, wherever DOS is referenced, the same reference applies to Windows as well, unless explicitly stated otherwise. 1- What is Partition Resizer 1.1 Why you need Partition Resizer OK, this is simple: if you have a disk partition (or more), and you want to change its size or position for any particular reason whatsoever, you have 3 options: a) Backup everything, use FDISK to delete the partition, re-create the partition and restore the data. b) Pay $60 to buy a program that you will use 3 times in your life ($20 per use) c) Use Partition Resizer Always remember: This program does not intend to replace FDISK. It's rather complementary to it. You will still need FDISK if you want to create and delete partitions. Partition Resizer processes only existing partitions. Also, Partition Resizer does not convert FAT16 (older DOS partitions) into FAT32. Windows 98 provides a tool that does this conversion. 1.2 How does it work? Well, this is the tricky part. The details are described in section 3, but I'll try to make a start from here. I assume that everybody understands the importance of partitioning. I also assume that most of you understand how partitioning is achieved. For those who don't, here it is: Partitioning is just a marking of territories on the physical disk's surface. At the first sector of the disk (sector 1, head 0, cylinder 0) resides an executable code block, which looks for the bootable partition, and runs it's boot sector code. That sector contains the information needed to divide the disk space into partitions. Later on, the boot sector (which is created by the OS's format utility) loads the OS Kernel (in DOS's case it loads the IO.SYS and the MSDOS.SYS), which continues the job by loading the information of all the partition structure into memory. Partition Resizer does two things: When moving, apart from moving the data, it changes the information contained in the partition structure. When resizing, it changes the file system's data, which is contained in the boot sector and the FAT area. Both partition and FAT FS structures are explained at section 3. 1.3 Is it safe? I have not heard of any case where version 1.2.0 (previous version) caused damage to a disk. This version also appears to work fine but even if the program has been tested with hundreds of partitions and partition combinations, and even if the program worked great till now, there might still be some incompatibilities or even bugs. In case you find a problem, please inform me ASAP. In order to avoid trouble, you should backup the most valuable data in your disk, those that cannot be replaced. If something happens, you'll only have to reinstall what's lost. Most of the partition combinations this program has been tested with are combinations created with DOS's (or Windows') FDISK, or compliant to it. If you have created a partition structure which is not compatible with DOS, the program will most probably encounter problems and refuse to work with the offending disk in order to protect your data. The typical DOS partition structure is described later on in this document (section 3). The program utilises a special recovery mechanism that allows resumption of the resizing or moving process even if it is interrupted by a reboot (most probably due to power failure). Without this recovery mechanism, if the program was interrupted during the resizing or moving process, it would be impossible to access the partition's data again. This program stores every single step, so it always knows what the last action was. For speed and safety reasons I use the CMOS's bytes 1,3 and 5 (the alarm bytes) to store the step counter number. Because the contents of the CMOS are preserved even when the power is off, the program can always find the last step and continue its work like nothing happened. If you don't believe it, test it. There is one problem I do not prevent: Bad sectors. In case your disk has bad sectors, the program will not run, in order to protect your data. It will make a surface scan before it starts, but if you are certain that your disk is free of defects, you may skip it. It would be better if you had your disk surface scanned with a commercial program (like Norton Disk Doctor or Windows' ScanDisk) before you run Partition Resizer. And note this: The program can be *really* dangerous, if you don't follow ALL precautions described in the README.1ST file. Please read it carefully before using the program. 1.4 Changes made to the previous version -Documentation update -Various important speed optimisations -Completely new resizing and moving engine -Automatic resizing of the extended partition when necessary -Major interface update -Strict partition structure validity verification -Full support for Hard Disks up to 2TB (using Int13 Extensions) -Introduction of Command Line Parameters -Corrected the drive letter nomination problem with FAT16 partitions -Corrected the problem with changing the current directory 2- Working with Partition Resizer 2.1 Safety Precautions As with every program that messes with your data, you should be extra careful. It is not difficult to make a mistake that will cost you valuable data. So, you MUST follow carefully the instructions contained in the file README.1ST, in order to ensure data safety. It would be a good idea to print TROUBLE.DOC file in order to have it available when something wrong happens. 2.2 Running the program: What does what The program will first look for the disk characteristics, it will scan the partition information, and it will identify and check all the DOS partitions of the disk. After some basic checks, it will continue with the main menu of the program. Here you have 4 choices. The first is resizing/moving a DOS partition or an extended partition. This option will resize a partition in order to make free space for a new partition to be created. It will also grow a partition if there is unallocated space available and the cluster size is big enough. You can also move the partition in the empty space. This way you will be able to change the order of the partitions in the disk. You can also resize extended partitions. The second option is used to change a FAT16 partition's cluster size. This will help you to make a small new partition able to grow up to any size you want. This option should be used ONLY on empty and formatted partitions, since it deletes all the data inside the partition. The third option will show you detailed information for every partition on the disk. This may sometimes help you find out which partition you want to move or resize. The last option will exit the program, and if you made any changes to the partition structure it will immediately reboot the machine, so that the new information will be loaded from the disk. Every choice but 4, will lead you to a menu where you will be asked to choose the partition which should be modified. Just enter the partition's number and press enter. Every partition description can have up to four flags. The first flag can be either P,L or E. These letters stand for Primary, Logical and Extended partition respectively. The flag * shows that the specified partition can be resized. Only partitions with * can be resized. The flag # shows which partitions can be moved. The flag ! shows that a partition is incompatible with the program, therefore it cannot be moved or resized. All partitions can be moved, but this is not always safe. I have tried moving FAT and HPFS partitions successfully, but I cannot be sure for every partition type. If you decide to move any other partition type but FAT, you will be proceeding at your own risk. The Drive letter indicated for a partition is the one originally assigned by DOS. Usage of some software drivers, like DblSpace or Stacker might alter the original drive letters. The user interface for resizing/moving partitions has been greatly simplified: appart from the use of graphics that make understanding the disk map easier, the most important functions of Partition Resizer are accessible through this screen. Using the Tab key, you can toggle between moving and resizing the currently selected partition. For advanced users, the space bar displays the extended partition of the disk and allows manipulation of its ends. By default, the extended partition is concealed, allowing the user to manipulate other partitions in a much simpler and effective way. Once finished, press enter to continue and accept the confirmation question. The screen will now clear, and you will be asked whether you want to perform a surface test or not. This is not necessary if you know that your disk is free of defects or if you performed a surface test recently, since it will take some time (from several seconds to 15 minutes, depending on the size of the partition). If you are uncertain, perform the surface test, since bad sectors can be dangerous to your data. If the program finds any bad sectors, it will quit immediately. If the surface test concludes normally, the program will start performing the requested changes. This may take from a few seconds to a few hours, so be prepared. If the program is terminated abnormally, p.e. in case of a power shutdown, don't worry, you can always reboot and run the program again. It will continue exactly from the point it stopped. After it finishes, you may proceed with more changes, or exit the program, which will boot your machine. Sounds easy? Well, it should be. But if you are confused, you better check out what's on the next section, just to get an idea about the whole partitioning system. If you still have questions, you can get help from friends, or contact me via my Internet addresses (see the end of this document). If you don't have access to Internet, you can send me a letter (postcard preferred) and I will try to help you as much as I can. Don't forget to tell me details about your system, your partitions, and send me a copy of the PRESIZER.LOG file. 2.3 Command Line Parameters Partition Resizer's execution can be customized to suit your needs with the following command line parameters: /drive:# When scanning for available physical drives (hard disks), Partition resizer will ignore all other drives except for the one specified in this parameter. # stands for the drive number (hard disk C: is number 0, D: is 1 and so on). For this version of Partition Resizer, only one drive can be specified each time the program runs. /killrescue If Partition Resizer was interrupted while resizing a partition, the next time it runs it will ask you to resume the operation. If you DO NOT WANT Partition Resizer to EVER resume the interrupted operation, use this option to permanently delete the rescue file and cleanup. This is a DANGEROUS parameter, since, if the resizing process is not resumed after abnormal interruption, the partition that was being processed (and in extreme cases other partitions as well) may be completely trashed. /newlog Creates an empty log file. By default, new log entries are appended to the existing log. This option allows to overwrite the existing entries. /noboot This switch forces the program to exit without rebooting after changes to the partition structure and/or file systems have been made. This is a DANGEROUS option, since if the user attempts to use the modified partition(s) before the machine is restarted, major damage can occur to the data. /readonly This switch allows the user to execute the program and modify partitions (resize or move them) without actually making any change whatsoever. The switch directly disables the disk write routine which is the only part of the program that can perform actual modifications to the disk. Therefore, this switch can be safely used for testing purposes, since all other functionallity (logging, rescue file creation etc.) will be available. Warning: because of slight changes to the rescue system, which now uses disk writing to extend the counter range, in some extreme cases the resumption process may not work correctly if this switch is specified. This is because the overflowing digits of the counter will be ignored. This has no impact on the disk integrity, but it may give false results (resumption may start at a step earlier than expected) IF the program is interrupted and the process is resumed. /textmode If you have any problems using the graphical interface, use this switch to work with an alternative (and similar to the graphic) interface in text mode. The text mode interface still provides full functionallity, but visual aid is less accurate and informative. 3- Technical Matters 3.1 The partition system The partition system is one of the most important things on the disk subsystem. It is a standard beyond File Systems and Operating Systems. The partition structure looks very much like the DOS directory structure. The root directory here is the root sector, the first sector of the disk. When the machine boots, bios loads this sector at address 7C00:0000, and jumps there. As you understand, there is code written at the beginning of that sector. This code searches the primary partition list to see which one is bootable, then loads its first sector (the boot sector) at the same address (7C00:0000) and it jumps there. After that, it is the operating system that takes control. Let's see some more details. Here is a detailed map of the root partition sector (sector 1, head 0, cylinder 0) (you may often see it as MBR, master boot record): Offset Description 0x000-0x1BD Boot code 0x1BE-0x1CD First Primary partition descriptor 0x1CE-0x1DD Second Primary partition descriptor 0x1DE-0x1ED Third Primary partition descriptor 0x1EE-0x1FD Fourth Primary partition descriptor 0x1FE-0x1FF System Signature word (0xAA55) Boot code is the executable code that was described above. The partition descriptors have the following form: Offset Description 0x0 Boot marking 0x1 Head \ 0x2 Sector & Cylinder 8-9 > Starting location 0x3 Cylinder 0-7 / 0x4 System Description 0x5 Head \ 0x6 Sector & Cylinder 8-9 > Ending location 0x7 Cylinder 0-7 / 0x8-0xB Relative sector 0xC-0xF Number of sectors in partition Boot marking is a byte value, which can be either 0 or the drive number (0x80). If it is 0x80 then the partition is the active partition of the disk (boot partition), and that's where the system boots from. The next 3 bytes contain the head, cylinder and sector where the partition begins. Sector and cylinder are stored in two bytes. Bits 0-7 of the cylinder value are stored in the second byte, while bits 8-9 are stored at the high bits of the first byte. The sector value is stored at bits 0-5 of the first byte. So, the word is bitmapped like this: FEDCBA98 76543210 CCCCCCCC CCSSSSSS 76543210 98543210 where C are Cylinder bits (the number below shows which cylinder bit is which) and S are Sector bits. Right after is the system byte, which is the identification byte for the partition. A value of 0 means that the partition is not being used, while other values depend on the file system. DOS uses values 1,4 and 6 for FAT12, FAT16 and BigDOS partitions respectively. A value of 5 means Extended partition, which is explained later on. Next, there is the ending location (sector) of the partition, and later on, the relative sector value. This is a number that shows the position of the partition relative to the present sector. So, for primary partitions, it's the starting sector of the partition (Primary partitions are the partitions that are described in the root of the partition structure. As we will see later on, there are partition descriptors in other places on the disk as well, which are called logical drives). The last item of the descriptor, is the partition length (in sectors). When the disk is operating in LBA mode, the CHS (cylinder-head-sector) values for starting and ending location are ignored. Mapping of the drive is not done in terms of CHS but with an absolute sector number. Thus, relative sector value and partition length are used for identifying the partition's territory on the disk. For disks greater than 8.4GB in size, CHS values are always invalid. In the root sector, there is space for 4 descriptors. Right after them, there is a word value of 0xAA55, which marks the sector as system sector. This value exists on every sector of the partition structure (including boot sectors) and if it doesn't exist, then the structure may probably be damaged. Now, concerning extended partitions, they are described as any other partition in the root sector, but their treatment is different. These partitions are specifically treated by the Operating Systems. They point to a sector which contains partition descriptors for other partitions and extended partitions, and so on. This is how we can have more than 4 partitions on a disk. Let's see a small graphic (sic) example: MBR 1st Ext 2nd Ext 3rd Ext ----------------------------------------------------- 1:p | 1:l | 1:l | 1:l | 2:p | 2:e-----------| 2:e-----------| 2:- | 3:e----| 3:- | 3:- | 3:- | 4:p | 4:- | 4:- | 4:- | ----------------------------------------------------- In this example, we see a map of a partition structure. MBR stands for Master Boot Record (root sector) and 1st, 2nd and 3rd Ext stand for 1st, 2nd and 3rd Extended partition nodes. 'p' stands for primary partition, 'e' stands for extended partition and 'l' stands for logical drive. The 'e' partition in the MBR, is called main or root or primary extended partition. This is because the whole extended partition structure is depending on that partition. Now, the starting location of the primary extended partition points to the 1st extended partition. The space that the primary extended partition allocates, is reserved for logical drives. The 1st extended partition (and the rest as well) contain information about their respective logical drives, in a way identical to the MBR (described above), but without the boot code part. Every extended partition has 4 descriptors as well, but only the first two are used: the first one identifies the corresponding logical drive, and the second contains and extended partition entry pointing to the next logical drive in the partition chain. So, the partition structure is a linked list structure, which can be as long as we like. (Every extended partition description sector has the 0xAA55 signature at its end, to identify it as a system sector). There are some geometry restrictions for partitions. Partitions must start at the beginning of a cylinder, and end at a cylinder's end. This is that starting location must always be Cyl: XXXX Head: (0 or 1) Sector 1 and the ending location must be Cyl: YYYY Head: k-1 Sector l, where k is the number of heads of the physical disk, and l the number of sectors per track of the physical disk. Also, if you delete one of the middle logical drives, (p.e. the 2nd Ext.) then the previous extended partition will be connected directly to the next, replacing the link. Geometry restricions are also effective in disks that work with LBA translation. If you want to see the whole thing yourself, you can make your primary DOS partition smaller, and create some new logical drives just to play with them. You can get much help from a commercial Disk Editor, and you can of course play with Partition Resizer. 3.2 The DOS (FAT16 and FAT12 only) filesystem structure The MBR executable code will load the boot partition's boot record. This is the second step of the booting procedure. And this is where the whole thing differs from OS to OS. We will only look at DOS's proceedings for now, since the rest OS's are less documented and more complicated (although on the next version of Partition Resizer I'll manage to resize OS/2 partitions, and if I get lucky enough, why not NTFS...). The DOS partition is rather simple: The first sector is the boot sector, right after there are two copies of the FAT (File Allocation Table), right then we have 32 sectors for the root directory, and finally we have clusters 0 and 1 (unused) and later on the rest of the clusters. The Boot record, is an executable code block, which is loaded by the MBR, and it makes some preparation in order to load the IO.SYS file, which is the DOS kernel (if we can call it a kernel... ;-)). This is useless to us, since only the processor can understand machine code, but the boot sector also contains useful information. This information begins at offset 3 of the sector and contains the following: Offset Description 0x03-0x0A OEM ID: This is a small string written by the formatter. 0x0B-0x0C Bytes per sector: This is always 512 (it depends on the physical disks characteristics). If you have a disk with a different value, please don't hesitate to inform me. Partition Resizer WON'T WORK FOR DISKS WITH SECTOR SIZE OTHER THAN 512! 0x0D Sectors per Cluster: The cluster is the basic block of information on a FAT drive. A FAT drive cannot have more than 65527 clusters. This size can limit the maximum size a partition can reach after resizing. 0x0E-0x0F Reserved sectors at beginning: This is normally 1, the boot sector. After these sectors, begins the FAT area. 0x10 FAT copies: Number of FAT copies. Normally there are two copies of FAT. 0x11-0x12 Root directory entries: This is normally 512. This shows the maximum number of files and directories that root directory can hold. This is because the root directory has a constant length (512 entries * 32 bytes/entry / 512 bytes/sector = 32 sectors) 0x13-0x14 Total sectors on disk (small): If we have less than 65536 sectors in the partition, this value contains the number. If it's more, then the number is stored in bytes 0x20-0x23. This is an entry that was left from the old DOS versions, when partitions could have up to 65536 sectors. 0x15 Media descriptor byte: This byte is always F8 for hard disks. 0x16-0x17 Sectors per FAT: This shows how many sectors does each FAT take up. This depends on how many clusters the partition has, and what is the FAT type (12bit/16bit). This can be from 1 to 255 sectors. 0x18-0x19 Sectors per track: Same as the physical disk's sectors per track value. 0x1A-0x1B Sides: Same as the physical disk's head number. 0x1C-0x1F Special hidden sectors: This is how many sectors exist between the partition's description sector and the boot sector. Usually one track. 0x20-0x23 Big total number of sectors: If we have more than 65536 sectors in the partition, their number is written here. 0x24-0x25 Physical drive number: This is the physical drive number (c:0x80, d:0x81 etc.). 0x26 Extended boot record signature: This marks an extended boot record. If it is 29, the disk was formatted by DOS 4.0 or later. 0x27-0x2A Volume serial number: This is the partition's serial number. 0x2B-0x35 Volume label: This is the partition's label string. 0x36-0x3D FS ID: This is a string that identifies a partition as 12bit FAT or 16bit FAT. This is a detailed description of the boot record information. This will help you to understand more about the FAT file system. The boot sector is the first sector of a DOS partition. The number of reserved sectors (which is normally 1) shows how many sectors we have before the FAT area. So in most cases, the first FAT sector is sector 2 of the partition (from now on, every sector number will be taken relatively from the beginning of the partition). The first FAT, who's length is given in the boot sector, contains entries that mark the partition's space allocation. Every file has a small descriptor of 32 bytes, which resides in its directory area (not in FAT). The directory area is itself a file, which is described in its parent directory, and so on until we reach root directory, which is a constant area in the partition (we'll see that later on). A word value in the file descriptor, tells DOS which is the file's first cluster. FAT consists of word values (or 12bit values if it is a 12bit FAT system), which begin from the first sector, and continue until the last one. Every value represents a cluster, which one is depending on the value's offset from the FAT's beginning. So, the 3rd word of the FAT stands for the 3rd cluster of the partition, and so on. So when DOS knows a file's first cluster, it's looking it up to find the value that is stored in the FAT's respective position. That value points to the next cluster of the file, and so on, until an EOF marking of 0xFFFF is found (0xFFF for 12bit FAT). Empty clusters are marked with 0 and bad clusters with 0xFFF7. This is how FAT works. Now, the first two positions of the FAT are reserved, and they have an identification code which is 0xFFFFFFF8 (0xFFFFF8 for 12bit FAT). The rest FATs (2nd, 3rd etc.) are identical to the first one. They are exact copies of the first FAT, and they begin right after the end of the first FAT. Right after the last FAT, resides the root directory. This is normally 32 sectors long, and contains 32 byte entries which describe the root directory's files and directories. Right after the root directory, begins the first cluster (cluster 0) which is unused, and so is for cluster 1. Right after these two clusters, begins the user's space, where the files are stored. This is the whole story about DOS's file system. This file system was designed to be fast (it's very easy to find the unallocated space) but it has certain disadvantages: One is the very large amount of unused space, which is caused by the use of clusters. For example, if you have a 340MB disk, you have to use 8192 bytes cluster size (16 sectors). This means that, if you write a file that is 1 or several bytes long, you will consume space of 8K. This could be resolved if we could use more than 65536 clusters in a DOS partition, which could mean a 20bit fat or more, in order to have clusters of 1 sector. Since this is not possible, there is another solution: Why should I have one partition with 8K cluster size, and not 2 partitions with 4K cluster size? The loss is lowered dramatically, and it would save many megs. This is not though always possible, since changing cluster size without loosing the existing data is quite complicated. I have decided not to add such functionality to the program, since the new Windows filesystem, FAT32, permanently solves the allocation problem. I strongly recommend the conversion of your existing FAT16 partitions into FAT32. This can be easily done with the use of the conversion utility provided by Microsoft and included in Windows 98 System tools collection. 3.3 The Windows FAT32 filesystem structure The FAT32 filesystem is quite similar to the FAT16 filesystem. The following differences exist: -FAT entries are now 32bit wide, allowing for a maximum of approximately 200 milion clusters in a single partition (actually, each FAT entry is 28bit wide, the upper 4 bits are reserved for future use and must always be 0). -The boot sector's information has been changed (see the table below) -The root directory does not necessarily reside in the beginning of the drive and it can grow to any size desirable. -FAT mirroring can be disabled In details, the boot sector entries are the following: Offset Description 0x03-0x0A OEM ID: This is a small string written by the formatter. 0x0B-0x0C Bytes per sector: This is always 512 (it depends on the physical disks characteristics). If you have a disk with a different value, please don't hesitate to inform me. Partition Resizer WON'T WORK FOR DISKS WITH SECTOR SIZE OTHER THAN 512! 0x0D Sectors per Cluster: The cluster is the basic block of information on a FAT drive. A FAT drive cannot have more than 65527 clusters. This size can limit the maximum size a partition can reach after resizing. 0x0E-0x0F Reserved sectors at beginning: first FAT sector number (0 based) 0x10 FAT copies: Number of FAT copies. Normally there are two copies of FAT. 0x11-0x14 Reserved, must be 0. 0x15 Media descriptor byte: This byte is always F8 for hard disks. 0x16-0x17 Reserved, must be 0 0x18-0x19 Sectors per track: Same as the physical disk's sectors per track value. 0x1A-0x1B Sides: Same as the physical disk's head number. 0x1C-0x1F Special hidden sectors: This is how many sectors exist between the partition's description sector and the boot sector. Usually one track. 0x20-0x23 Big total number of sectors: If we have more than 65536 sectors in the partition, their number is written here. 0x24-0x27 Big Sectors per FAT value (old SPF value is now reserved). 0x28-0x29 Flags used for specifying FAT mirroring properties. 0x2A-0x2B Major and minor version of the file system. 0x2C-0x2F Root start: The first cluster (start) of the root directory. 0x30-0x31 File System sector number: offset of the file system sector (see below). 0x32-0x33 Backup Boot Sector: offset of the backup copy of this sector. 0x34-0x3F Reserved. 0x40 Physical drive number: This is the physical drive number (c:0x80, d:0x81 etc.). 0x41 Reserved. 0x42 Extended boot record signature: This marks an extended boot record. If it is 29, the disk was formatted by DOS 4.0 or later. 0x43-0x46 Volume serial number: This is the partition's serial number. 0x47-0x51 Volume label: This is the partition's label string. 0x52-0x59 FS ID: This is a string that identifies a partition as FAT32. After this boot sector, the File System Sector exists, containing the following information: 0x1E8-0x1EB Free cluster count: contains the number of free clusters in the drive (used to speed up free space calculation). If it is -1 the value is recalculated. 0x1EC-0x1EF First free cluster: number of the first available cluster in the partition. I will not go into more detailed explaination of the FAT32 file system. For more information, please visit the Microsoft Developers Library at http://www.microsoft.com/msdn and go to SDK Documentation - Platform SDK - Windows Base Services - Windows 95 Features - Windows 95 Reference - FAT32 API Reference - Structures. 4- Partitioning Techniques 4.1 Deciding what you want Well, OK, you've got the program. But now what happens? Where will you create the proper space for a new partition? And which partition is the one you want to shrink or grow? How should you place the partitions in the empty space to order them as you like? How will you grow a partition which refuses to grow more? First of all, you have to decide what you want. Take a look at the partition list that FDISK or Partition Resizer provide you. Decide which partitions you need to resize. You may recognise them by their size, drive letter or serial numbers. Then you'll have to think what the new sizes will be. Remember that what's inside the extended partition cannot get out of it, and what's outside cannot get inside either. Now, here are some useful techniques to use in certain situations. Just take a look to see if they meet your needs. 4.2 Merging many small partitions into a larger one Sometimes, you get your disk divided into three or four partitions, which is not a useful thing. Until now, the only solution was to backup all your data, delete the whole partition structure, and then create a large partition to put your data inside. Partition Resizer can resolve the problem without any backing up. It's much faster and easier. Just do the following: a. Decide which partition will be the one to remain. Normally, you should choose a primary partition. The problem is if it can grow enough. Decide what is the size the partition will finally grow to, and check if your primary partition can grow to that size. If it can't, go to step b, otherwise read step c. b. If you want to create a partition that can grow enough for your needs, you will have to empty your primary partition. To do this, you have to shrink it to its minimum, while growing a logical drive. This can be done by shrinking the primary partition, expanding downwards the extended partition, moving the first logical drive to the beginning of the extended partition, and growing it to the max. Then, exit the program, move as much files as you can from the primary partition to the grown logical drive, defrag the primary partition, and repeat step b until the primary partition is empty. When you empty it, use the program to change its cluster size that matches your needs. You can provide the program with the desired size, which is the size you want the partition to have when you finish the whole process. Partition Resizer will then suggest you a cluster size to apply to the partition, which is the optimum size for the given desired partition size. If this was your boot partition, you will have to make it a system partition again, so run SYS to do that. c. Now that your primary partition is able to grow enough, start moving data into it. Try to get data from small partitions, so that you can finish with them early and get rid of them. If you filled up the primary partition and there's still data in the partition which you are emptying, move data from the emptying partition to other partitions, in order to empty it faster. When the partition is empty, you can delete it with FDISK. If you cannot empty it, then defrag it, shrink it to its minimum, and move it to the end of the empty space created, grow the previous partition to reclaim the empty space created, exit the program, and move the rest of the data remaining into the grown partition. Repeat this until you empty the partition, and then delete it with FDISK. d. One of the small partitions is now deleted. You can now move all the other logical drives to the end of the empty space, and resize the extended partition in order to make more space to grow the primary partition. Then choose another partition and repeat step c until you empty and delete all the logical drives. With the last one, you can delete the extended partition too. And presto! You can now grow the primary partition to fill all the empty space in the disk. 4.3 Splitting a partition in two This technique is much alike the previous one. Suppose you have one primary partition, and you want to split it in two partitions. This is faster and easier than the previous procedure, just do the following: a. Defrag the primary partition, and then shrink it to the minimum. This way, you will create empty space for the new partition. b. Using FDISK create an extended partition, and then a logical drive in it. Format the logical drive, and run Partition Resizer. You will now have to decide the final size of the new partition, in order to change its cluster size while it is still empty. When you decide the final size, choose the third option of Partition Resizer's main menu, and give as desired size the size you decided. The program will suggest you a cluster size that is optimum for the partition, and you should apply that size. c. When you finish creating and modifying the new partition, exit the program, and move the data you want in the new partition. Then, shrink the primary partition again (defraging is necessary here) grow the logical drive to the maximum. Repeat this step, until you reach the desired size. 4.4 Playing with partitions' sizes and positions And now, some general advice about partition resizing: a. When shrinking a partition, always defrag it first. This will leave space at the end of the partition, which will be freed by the program. The less space you have at the end of the partition, the less the shrinking will be. When defraging take special care for the unmovable files: They must be moved too, so change their attributes before defraging the disk. System files are a special case of unmovable files. You must be extra careful with these. Check the TROUBLE.DOC to see more info about the system files. b. Although Partition Resizer can move primary partitions, you will rarely need to do this. You should always leave your DOS primary partitions in their original place, unless you absolutely need to move them. This will not harm the partition, but it might leave unused space before the primary partition which will never be used by DOS's FDISK. Warning: if you move a primary DOS partition, you might not be able to boot from that partition! c. If you want to install a new operating system, you may have to delete much of your data in the DOS partition, since you cannot move that data in the new partition. So, you will only have to shrink your DOS partition once. d. Always follow the safety rules described in README.1ST. Playing with your data can be REALLY dangerous sometimes, so be very careful. 4.5 Lack of features and possible workarounds Partition Resizer required a lot of time for its development and the development of its upgrades. Time which was spent solely by me, and which is of course valuable. I never regret the time I spent on this project, and I feel that my efforts have been paid off by the success of the program in an international level. There are though some features that Partition Resizer always lacked, and will probably continue to lack, because I believe that they are not necessary or workarounds can be used instead, while the time and effort they require for development is more than what I can invest (or am willing to invest). These features and possible workarounds are the following: Problem: Partition Resizer does not resize non-FAT partitions. Workaround: Nothing I can think of... another program maybe? Problem: Partition Resizer does not change the cluster size in a non-destructive way. Workaround: Several workarounds exist. The best in my opinion, that is of course if it can be applied, is to change the filesystem to FAT32. This will create partitions with minimal cluster sizes (4K) and practically unlimited maximum size. If FAT32 is not available, then try creating a new partition of the desired cluster size, and move the data in there (see PRESIZER.FAQ for a more detailed description of the process) Problem: Partition Resizer does not perform creation or deletion of partitions. Workaround: FDISK does. Please use it. Problem: Partition Resizer's user interface sucks. Workaround: Pretend that you like the user interface. 5- Credits and addresses There used to be a huge list of thanksgivings here, but I decided that it will take ages to update it (especially after 2 years). So I will briefly (but not less intensively) thank all of the people who helped the creation and continuous development of this program, with their suggestions, their feedback, and most of all their support that comes from the appreciation of my work. I also thank you, for spending the time to read this document and for using my program. I hope that the technical info included in here will seriously help many of you to create your own programs. If you find this program useful, you can always send me a postcard to the following address: John Lagonikas 17 Lycourgou Str. 16675 Glyfada ATHENS, GREECE Since the e-mail flow concerning the program is always increasing, and reached a peak of several messages per day that had to be answered in detail, I would kindly request that you think twice before asking for advice or information. So, please, before sending the message, take a look at PRESIZER.FAQ to see if the answer to your questions (or your prayers) is in there. Please try to find some different passive sources (web pages, documentation, books etc.) that might help solving your problem. If all else fails, try contacting me at the address: zeleps@usa.net Commentary e-mail is welcome, but it will probably not be answered. The official home page of Partition Resizer is currently (28/10/98) located at: http://members.xoom.com/Zeleps If you cannot find the page at this location for any reason, you can perform a Web search with the keywords "Partition Resizer Zeleps" to locate it. Thank you again for reading this document and for using Partition Resizer! ------||------ .