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SD Card Speed Improvement for FZ80

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- Removed wait routines for FZ80 in SD driver.  Latest FPGA code does not require them.
- Minor improvements to disk layout documentation.
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Wayne Warthen
2024-08-04 12:12:16 -07:00
parent cd70a62d67
commit e68cbded97
9 changed files with 28 additions and 14 deletions
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27
Source/Doc/SystemGuide.md
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@@ -265,9 +265,24 @@ hence the name "Common".
# Disk Layout
RomWBW supports and automatically detects 2 different disk layouts
known as Modern (hd1k) and Classic (hd512). Specifics of these two
variants are described in separate sections below.
RomWBW supports two hard disk layouts: the Classic layout used by
RomWBW with 512 directory entries per slice and a Modern layout with
1024 directory entries per slice. These layouts are referred to as
hd512 and hd1k respectively.
WARNING: You **can not** mix the two hard disk layouts on one hard
disk device. You can use different layouts on different hard disk
devices in a single system though.
RomWBW determines which of the hard disk layouts to use for a given
hard disk device based on whether there is a RomWBW hard disk
partition on the disk containing the slices. If there is no RomWBW
partition, then RomWBW will assume the 512 directory entry format for
all slices and will assume the slices start at the first sector of
the hard disk. If there is a RomWBW partition on the hard disk
device, then RomWBW will assume the 1024 directory entry format for
all slices and will assume the slices are located in the defined
partition.
RomWBW supports up to 256 CP/M slices (0-255). Under hd512, the slices
begin at the start of the hard disk. Under hd1k, the slices reside
@@ -282,8 +297,10 @@ geometry for operating systems:
- Cylinder = 16 Tracks (256 Sectors per Cylinder, 128KB per Cylinder)
If one is used, the FAT Partition must not overlap the CP/M slices.
In the case of hd1k, the CP/M slices are within partition 0x2E and the
FAT partition must not start after the last CP/M slice, but does not need to start immediately after it nor does it need to extend to the end of the hard disk.
The FAT partition does not need to start immediately after the CP/M
slices nor does it need to extend to the end of the hard disk. Its
location and size are entirely determined by its corresponding
partition table entry.
Drive letters in CP/M are ASSIGNed to the numbered slices as desired.
At boot, RomWBW automatically assigns up to 8 slices to drive letters