All About Windows 95 Operating System Release 2 What is FAT32? Sean Erwin
Versions of Windows 95 older than OSR2, as well as any DOS version, operate on a file system called FAT16 (or FAT12 in some cases). The existence of large hard drives has led to large partition sizes, which mean large cluster sizes and wasted space:
Under FAT16, a smaller cluster size is better, because a small file takes up a whole cluster if there is even one byte in it; the leftover space is called "slack."
Where: S=Slack CS=Cluster Size AFSc=Average File Size per cluster NF=Number of Files
There is a DOS utility called chkdrv which will calculate the slack on a given FAT16 partition (I have not dared to run this on my FAT32 partitions).
The table below shows the maximum partition size to get clusters of a given size. You cannot format a hard drive under DOS with a cluster size less than 2K.
Cluster size
Partition
FAT
Notes
size
type
4K (4096 bytes)
16 MB
FAT12
2K (2048 bytes)
32 MB
FAT16
(DOS versions < 4.0)
2K (2048 bytes)
128 MB
FAT16
(DOS versions >= 4.0)
4K (4096 bytes)
256 MB
FAT16
8K (8192 bytes)
512 MB
FAT16
16K (16384 bytes)
1 GB
FAT16
32K (32768 bytes)
2 GB
FAT16
Example To have a cluster size no larger than 8K under FAT16, your partition must be 511MB or smaller.
FAT16 does not support partitions larger than 2GB.
FAT32 is an improvement, as it supports drives up to 2 Terabytes in size, and cluster sizes are 4K for partitions smaller than 8GB:
The following cluster sizes are the defaults for FAT32 drives:
Note that the minimum size of a FAT32 partition created with FDISK is 512MB, that is, you cannot make FDISK/FORMAT format a drive with the FAT32 file system if it is smaller than 512MB. If you are using Partition Magic 3.0 to convert a FAT16 partition to FAT32, it will convert partitions smaller than 512MB. I believe the smallest partition Parition Magic 3.0 will convert is 261MB, but I am not certain.
Can I use earlier versions of Windows 95 with FAT32? Is any operating system other than OSR2 compatible with FAT32? Is Windows NT (any version) compatible with FAT32?
No, no, and no. Microsoft has no plans of enabling NT support for FAT32 volumes before the release of NT 5.
Is FAT32 compatible with my Motherboard?
For IDE drives, your motherboard BIOS must support LBA mode to be compatible with FAT32 (that is, LBA mode must be enabled). Many 486 motherboards do not support LBA mode. Some BIOSes on older Pentium motherboards (as recent as February 1996) do not support IDE drives over 2GB. If you run an IDE HD off such a motherboard, then you have to use a third-party disk manager to access the entire drive. Short answer: if your motherboard is new, then certainly yes. If your motherboard supports Pentium processors, then very probably yes. If your motherboard is a (not new) 486 motherboard, then maybe. If it is a 386 motherboard, then good luck!
Of course, if you are using a controller card BIOS instead of the MB BIOS, then you are subject to limitations (or lack thereof) of the controller card BIOS. The absolute upper limit for a single partition under most BIOSes and SCSI configurations is approximately 8GB. For single partitions larger than 8GB, the controller must support Int 13 extensions.
Are there issues with FAT32 and third party Disk Managers such as OnTrack or EZ Drive?
Yes. The largest partition you can create with these Disk Managers is 2.1GB. If your HD is larger than this, and you are using a Disk Manager, you must use multiple partitions. If your MB BIOS is dated Jan 1996 or older, you may have to use a Disk Manager to access all of an IDE HD larger than 2.1GB. See this Knowledge Base Article for other issues with Disk Managers.
How do I format a (hard) disk with FAT32?
With the FDISK utility in OSR2. FDISK will only allow you to put FAT32 on drives larger than 512MB. Inside FDISK, you must enable "large disk support," to choose FAT32. After exiting FDISK and rebooting, FORMAT (use the OSR2 version only) the drive. NOTE that you must manually reboot after exiting the OSR2 version of FDISK, this is not automatic as in previous versions of FDISK. If you do not reboot between FDISKing and FORMATing, you will get strange-looking error messages.
I want to format my drive with FAT32 before I install Windows 95 OSR2. How do I do this?
You need an OSR2 startup disk for this. To make one from the CD, do the following:
Method 1:
Begin the install of OSR2. Proceed until you are asked if you want a startup disk. Answer yes, and follow the instructions. After the startup disk is made, cancel the install. Now you have a bootable floppy with the new version of FDISK, FORMAT, etc, to do with as you see fit.
Method 2:
You can also make an OSR2 startup disk if you have: 1) any version of Windows 95 installed on your system, 2) the OSR2 CDROM and 3) A floppy disk.
To make an OSR2 startup disk from an older version of Windows 95:
1. Put your Windows 95 OSR2 CD in the CDROM drive. Put a blank floppy in the A: drive.
2. Go to Control Panel > Add/Remove Programs > Startup Disk, and click the Create Disk button. Follow the prompts.
This will create an OSR2 startup disk, with the new FDISK, FORMAT, etc. Method 2 courtesy Lee Chapelle.
Is there a FAT16 > FAT32 conversion utility?
PowerQuest has released one, as part of Partition Magic version 3.0. Here's a link to their online order form. It is possible to "force" an upgrade of an existing Windows 95 installation, and then convert FAT16 to FAT32 after installation of OSR2. See below for details.
Case Study: On a 1.2GB drive, formatted as a single partition, before conversion from FAT16 to FAT32 (via Partition Magic 3.0), there was 58MB free space. After conversion, there was 268MB free space. Your results will vary.
Microsoft has also developed a FAT16 > FAT32 (one way only) conversion utility, named "CVT.EXE". This conversion utility has only been released to beta testers of OSR2 and Memphis. It has not been distributed via MSDN.
How can I verify that my Hard Drive is formatted with FAT32?
Right click on the drive icon in My Computer or Windows Explorer. Choose properties. You should see a screen like that at right. The "Type:" line should indicate FAT32.
Can I install compression on a FAT32 partition?
No. Interestingly, if you use FAT16 with OSR2, and you try to run Compression Agent, you will get an error telling you to install Plus!. Let me know if you can find a workaround other than installing Plus!. My question to Microsoft: Why did you guys put Compression Agent in OSR2, and then disable it in this way? Seems misleading to me to include a component in OSR2 that (on purpose) doesn't work.
How does FAT32 affect system performance?
To quote the Microsoft Knowledge Base article referenced below:
"For most users, FAT32 will have a negligible performance impact. Some programs may see a slight performance gain from FAT32. In other programs, particularly those heavily dependent on large sequential read or write operations, FAT32 may result in a modest performance degradation."
I have seen seemingly reputable information stating that "the more clusters, the slower the performance." For instance, the closer to 8GB your partition gets, the more 4K clusters, and the slower the performance. (However, as your partition gets bigger, your slack vs. FAT16 improves.) The FAT32 aware versions of Defrag and Scandisk do run slower, though, and the Advanced Power Management (APM) feature of OSR2, which spins down the hard disk when inactive, may give an impression of slower performance. To turn off APM, go to Control Panel > Power and uncheck the "Allow Windows to manage power use on this computer" box.
Benchmarking:
If you publish benchmarks for FAT32 vs FAT16 on the web, I will provide a link to them here:
Will my present version of (any disk utility software such as Norton Utilities) work on a FAT32 drive?
Norton Utilities 2.0 and Norton Antivirus 2.0 now support FAT32. About application compatibility in general with FAT32: Most any application should have no problems, including backup software. However, any application which accesses/reads the Master Boot Record will no longer be able to, as with FAT32 the Master Boot Record is no longer in a fixed position on the disk. This raises an interesting question, namely, will viruses which infect the Master Boot Record of a FAT16 or FAT12 volume also be able to infect the Master Boot Record of a FAT32 volume? Or will new viruses have to be written?
Can I format an Iomega 1GB JAZ disk with FAT32?
Yes, but you must be using Iomega JAZ Tools/driver version 5.0 or later. Earlier versions are not FAT32-aware.
I don't care about FAT32. Will OSR2 work with FAT16? Or do I have to use FAT32?
OSR2 does not require FAT32. OSR2 works just fine with FAT16.
All I want is for my DOS games to work. Are there any new issues with OSR2 or FAT32 with DOS games?
Since you can no longer boot via F4 to an earlier version of DOS, the easiest thing to do is to run them on the DOS (ver 7.1) under OSR2. Neither OSR2 nor FAT32 should have any effect on the performance of your DOS games. However, see below in the bugs section about a bug involving the real-mode memory manager emm386.exe.
If I install OSR2 on a brand name PC or laptop that did not ship with OSR2, will it invalidate my tech support?
Yes. And Microsoft will also not support you. Many system builders (such as Dell) may bundle OSR2 with your system, but do not use FAT32, and furthermore, state that if you do use FAT32, then this will invalidate your tech support/warranty. Consider this carefully before making a decision to install OSR2 or use FAT32. If you do this, and end up with a serious problem, you could end up totally hosed. Since OSR2 is relatively new, not all issues/bugs are yet known. Use at your own risk.
I'm having this interesting problem under Windows 95 (original release or Service Pack 1). You see, (insert description of your interesting problem here). Will installing OSR2 fix it?
No.
Can you elaborate?
There is nothing unique to OSR2 which fixes problems in earlier versions of Windows 95. Bugs in earlier versions of Windows 95 are either:
1. Fixed by patches available for free from Microsoft or other vendors.
2. Can be fixed by manually editing the registry/system files.
3. Not fixed by any means, and also not fixed in OSR2.
What is unique to OSR2 are new features & capabilities such as FAT32, APM improvements, Bus Mastering support, PCMCIA enhancements, CDFS enhancements, MMX support, etc. See Microsoft's Market Bulletin on OSR2 for a complete list. Of course, any patches/fixes for Windows 95 currently available from Microsoft are integrated into OSR2. Do NOT install any of these patches/fixes on top of OSR2.
Well, the above statement isn't entirely accurate. There is at least one exception, ie, the case of a bug in Win95 that can only be fixed by installing OSR2. Here it is, courtesy Michael Kenny:
The particular interesting problem I am having under Windows 95 has to do with multihoming TCPIP to succesfully bind TCP to both an network adapter with a static IP address for my corporate LAN and to connect with TCP via a Dial Up Adapter using DHCP.
Long story short: there's a bug in configuring TCPIP and different DNS's for each adapter in versions of Windows 95 prior to OSR2.
When I look at the description of OSR2 I see that it lists improvements in TCP/IP multihoming for LAN/WAN and WAN/WAN connections. This may solve part of my problem. However, I looked and looked for the TCP/IP update. It's not listed on the "Yes/No" chart which describes which peices of OSR2 one can download. Nor can I find it anywhere else on the site.
So it appears that there is at least on interesting problem for which the only fix (so far) is the unpurchaseable [unbundled with hardware] OSR2. Just thought I'd drop you a note on it. Of course, if you happen to know where to get the updated TCP/IP part of OSR2, that would be very nice as well.
If you find more exceptions to my rule, please let me know!
Where can I find out more about issues with OSR2 and specific hardware or software?
