Author: Copyright (C) 2014 by CiderPress authors

Opening a Volume

In some circumstances it is useful to open a raw disk volume. Two common examples are ProDOS-formatted 1.4MB floppy disks and CFFA flash cards. CiderPress allows you to access ProDOS and HFS filesystems directly.

WARNING: it's possible to destroy all data on your hard drive. Make sure you're opening the right volume! When in doubt, open the disk in "read only" mode by checking the "read only" checkbox. As a safety measure, "read only" is set by default, and CiderPress will not allow you to open "C:\" or physical drive 0 if read-only mode is disabled. Always close the volume (with File->Close) before ejecting removable media.

Not all devices will work under all operating systems. Please check the hardware compatibility list on the faddenSoft web site.

Disks can be opened as "logical" or "physical" volumes in Windows. Understanding the distinction is important. The basic difference is that a "logical" volume has a drive letter associated with it (e.g. "A:\" for your first floppy drive), while a "physical" volume is numbered (e.g. physical device 0 is your primary hard drive). From the operating system's perspective, a "physical" disk has a partition table in block 0 that describes one or more "logical" volumes. Floppy disks are an exception; for them, "logical" and "physical" are equivalent. A CF card reader may present itself to the system as a physical disk, in which case Windows will try to find a partition table in block 0.

ProDOS and HFS volumes don't have a partition table in block 0, which can cause some confusion. In some cases you will see a "physical" volume for the CF card but no "logical" volume. In others the "logical" volume will appear and will be as large as the "physical" disk. If Windows thinks it has a valid partition table, the "logical" volume may be a small subset of the "physical" disk.

The bottom line is that it's best to use "physical" disks whenever possible. However, it's not always possible. You can't treat a floppy drive as a "physical" disk in Windows 2000, and access to "physical" hard drives in Win9x/ME is tricky. You have to access floppies as "logical" volumes under Win2K, but if you do that under Win98 you will have terrible performance in some circumstances. It would be nice if CiderPress could automatically do the right thing in all cases, but every CF card reader is different, so CiderPress tries not to limit your options.

CD-ROM drives have their own access method. No version of Windows makes it easy to read blocks from a CD-ROM with an unrecognized filesystem format. Under Win2K/XP, CiderPress relies on a technology called SPTI (SCSI Pass-Through Interface) to access the disc. Select the drive you want from the "logical" list, by letter (e.g. "D:\"). Under Win98/ME, it's necessary to use an ASPI driver (Advanced SCSI Programming Interface), just like CD recording applications do. CiderPress will look for "wnaspi32.dll", and use it if found (Win98 includes it -- look in the About box to see if it was loaded successfully). CD-ROM drives show up in the "physical" list, described by manufacturer and model number. Some external CD-ROM drives may not show up in the list.

Generally speaking, SPTI and ASPI have equivalent performance. The only notable difference is that SPTI requires exclusive access to a device, so you can't have a CD-ROM open in the file list and then open it in the volume copier. Some ASPI layers will pick up devices other than CD-ROM drives, such as SCSI hard drives, Zip drives, and even CF card readers.

Hard drives partitioned for an Apple II or Macintosh can be accessed if attached to an IDE or SCSI connector. Under Win9x/ME you can only access drives that the ASPI layer can find, which usually means you can only get to SCSI hard drives.

Here's what you should do:

In Windows 2000/XP:

- Use "A:\" to access your floppy drive.
- Use "D:\" (or something similar) to access your CD-ROM drive.
- Use "physical disk N" to access hard drives.
- Use "physical disk N" to access your CF card if that's an option. If not, use the logical drive (e.g. "M:\"), but be aware that the card may appear to have a different size when formatted for CFFA vs. Windows. With some card readers, the size shown for the card may be wildly inaccurate, especially on Win2K or earlier.

In Windows 9x/ME:

- Use "floppy drive N" to access floppies. CiderPress will actually hide "A:\" if the disk doesn't have a Windows filesystem, because "logical" access to such disks is very slow. (It will otherwise show it, so you can identify your Windows disks.) After overwriting a disk, Windows will continue to show the old volume label until you eject the disk.
- Select your CD-ROM drive by vendor name and model number.
- Select SCSI hard drives by vendor name and model number.
- Use the logical drive (e.g. "M:\") to access CF cards. If the logical drive shows up in the list when you insert a Windows-formatted card but not with a ProDOS-formatted card, you have a brain-damaged CF card reader driver, and it's not going to work.

Access to physical devices other than floppy disks in Win2K/XP requires "administrator" privileges.

If you un-check the "read only" box, Win2K/XP will not allow you to open the volume a second time, e.g. you can't have a disk open in read-write mode and then open it again in the volume copier.

The "filename" for physical disks will show up as two digits, e.g. "81:\" for the second physical disk. This is an artifact of the way the PC BIOS works. CD-ROMs and hard drives under Win9x/ME will look like "ASPI:0:1:0\".

You cannot create or access files larger than 2GB under Win9x/ME. This is an operating system limit, and cannot be circumvented.

CiderPress has a self-imposed 8GB volume limit (as a "reasonableness" test to keep it from running amok). This should be large enough to handle CF cards and hard drives partitioned for use on an Apple II.

CiderPress does not detect media ejections or swapping. Do not eject disks or CF cards while CiderPress has them open.

In some cases you may need to be patient! Scanning the contents of a CD-ROM with 10,000 files spread across several 32MB ProDOS volumes can take a few minutes.