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Re: FAT without the fat, alternate SD IO
My next step is to get to the base raw SD initialization and read/write.
The idea is more compact code that has no fat artifacts or code needed to handle it as fat. to me other than a few keep out areas the 1gb sd is just a bag of 2,097,152 (0x200000) blocks of 512 bytes. The idea is to have a super directory (tag and bag) of smaller CP/M sized (8mb or smaller)? "disks" that can be loaded as needed. Each would be file system only.? ?The CP/M OS is loaded from EProm as pseudo boot track.? The?CP/M file systems can be loaded on the fly as its an offset and DPH/DPB that describe the media.? SELDISK in the BIOS selects a drive (up to 16) but usual systems limit that due to buffer space and ALLOC space (256 byte per 8MB using 4K alloc) needs. But the base number of drives can be altered on the fly and its a minor coding task to make that a loadable system variable rather than BIOS fixed? as done often. By doing that it become easy to make a really large device usable. Seems to work fine for 128 or 256mb CF. PC comparability for the SD is not used as files needed are simply transferred via USB-serial to Z80MC.? By treating the SD as a non removable memory it lightens the code.? Doing that allows for a monitor, tag and bag OS, BIOS, CP/M image (62K system) plus extras to fit in 32K eprom. This is a result of thinking outside of the CP/M alteration guide and 4 floppies. Allison |
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Re: FAT without the fat, alternate SD IO
That may be it, I really don't enjoy parsing the FAT structure.? Accessing the device on the
LBA makes more sense to me as its really just a large number of addressable blocks.? I've done that with IDE/CF for years and its faster.? Also makes it more in common with romdisk. With the advent of large Eproms romdisk makes having base software available.? The 32K mapping for low address space makes it easy to have the rough equivilent of 8"SSSD disk (about 240K) for those that remember CP/M 2.2. Now to wade through the source and make sure I captured the needed code. NSDOS is a tag and bag DOS.? Its structure is simple. ;***
;? ?Tag-n-Bag a primitive file system for mass storage device.
;? ?
;? ?Directory size typically 4 logical blocks (256, 512)
;? ?Empty entry is all spaces or zeros
;
;? ?16 bytes per entry FILE:
;? ? ? Byte? 0-7 symbolic name 8 char (ascii 7 bit)
;? ? ? ? ? ? 8,9 disk address (starting block)
;? ? ? ? ? 10,11 number of blocks in file
;? ? ? ? ? ? ?12 file type
;? ? ? ? ? ? ? ? ? 0=undefined
;? ? ? ? ? ? ? ? ? 1=executable 14-15 start addr
;? ? ? ? ? ? ? ? ? 2=data file?
;? ? ? ? ? 14-15 type dependent, start address
;
;? ?ODS:? device is a collection of sequential blocks
;? ? ? ? ?Block Logical size is 65535 max
;? ? ? ? ?NS* floppy has a boot block at 0000h
;? ? ? ? ?Block at logical 0000h is start of directory. ;==========================================================
The base version of that had no scatter gather mechanism so the NS* system had? a utillity to compact the disk.? ? Another weel know OS that was similar was DEC RT-11. Why is it interesting,,,,? Any file can be a directory. Allison |
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Re: FAT without the fat, alternate SD IO
Hi Allison, You can just cut the FAT out.? Under the FAT is nothing more than reading/writing LBA. Cheers, Josh
On Friday, December 15, 2023 at 09:43:21 p.m. EST, ajparent1/kb1gmx <kb1gmx@...> wrote:
Planning a new Eprom for the Z80MC.. The basic plan is a tag and bag file system.? Anyone that has used NSdos that was such a file system.? The plan s to rewrite NSDOS to use anything but floppy (and their hard sector controller).? SD is the logical device. So to do this I need to access the card at the sector level likely LBA. My first pass is a handful of routines needed: There is no on device file system assumed such as FAT16 or other partition, or file table, or allocation table... So the first usable block to max block (end of media!)? need to be known. The assumption is 1 block is 512 bytes. SD _RESET SD_initial? ? initialize where the SD parameters are pulled from the device. SD_Read_block SD_write_block The code needs to be compact so most FAT code contains unneeded functions. I assume the SD will have wasted space as 1 or 2gb is far larger than needed. Storage is cheap these days. Most z80 systems loaded with programs and applications are relatively small.? ?My largest system uses 128mb CF and I fill about 45mb of it.? Also PC readable is not required.? Most examples found are not Z80 asm or are full FAT and most examples are in C.? C on Z80 tends to produce large code.? A pointer or example code would be helpful.? The ZMCV15 code has it but ts full FAT. ? Allison |
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FAT without the fat, alternate SD IO
Planning a new Eprom for the Z80MC..
The basic plan is a tag and bag file system.? Anyone that has used NSdos that was such a file system.? The plan s to rewrite NSDOS to use anything but floppy (and their hard sector controller).? SD is the logical device. So to do this I need to access the card at the sector level likely LBA. My first pass is a handful of routines needed: There is no on device file system assumed such as FAT16 or other partition, or file table, or allocation table... So the first usable block to max block (end of media!)? need to be known. The assumption is 1 block is 512 bytes. SD _RESET SD_initial? ? initialize where the SD parameters are pulled from the device. SD_Read_block SD_write_block The code needs to be compact so most FAT code contains unneeded functions. I assume the SD will have wasted space as 1 or 2gb is far larger than needed. Storage is cheap these days. Most z80 systems loaded with programs and applications are relatively small.? ?My largest system uses 128mb CF and I fill about 45mb of it.? Also PC readable is not required.? Most examples found are not Z80 asm or are full FAT and most examples are in C.? C on Z80 tends to produce large code.? A pointer or example code would be helpful.? The ZMCV15 code has it but ts full FAT. ? Allison |
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Re: Where's the CPM files
开云体育
that was it josh.? try it now and it should work.?
From: [email protected] <[email protected]> on behalf of joshbensadon via groups.io <joshbensadon@...>
Sent: December 8, 2023 10:43 AM To: [email protected] <[email protected]> Subject: Re: [Z80MC] Where's the CPM files ?
When I go to files section,? I should see "NEW/UPLOAD" button (like I do in COSMAC GROUP).? But I don't see it.
Is might be a permissions thing? |
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Re: Where's the CPM files
Ok, right, this isn't the COSMAC group.?? Thanks.
On Wednesday, December 6, 2023 at 11:28:30 a.m. EST, ajparent1/kb1gmx <kb1gmx@...> wrote:
Hi Josh, Best place is the files section of the group. While use PCs and program them even the older systems are my thing. I still have the old don't you wish you have now what DEC had then. For that I boot the MicroVAX as The OpenVMS Language Senstive Editor LSE and cross platform systems are still cleaner than some of the current PCisms.? Linux made than less painful. The only time I've done SD so far I made FAT file of 256mb on a fresh 1GB device?so that its allocated sequentially.? Then located the staring Block number and addressed the blocks in it as LBA starting at xxxxxxH? to the PC its just a block that's allocated with whatever inside.? The system then doesn't need to know FAT at all.? The PC only created the larger container file and allowed me to know the stating address. The CP/M system populated the container file as sectors starting at xxxxxh.? The PC was involved but minimally to initialize (create Fat 32 container file) the disk. As to BIOS design and storage allocation its not obvious but Alloc is a bit map that has one bit per addressable block for the current allocation size.? I had to figure that out in late 1979 when I got CP/M2.2 after running 1.3 and 1.4 in prior years.? So Alloc map for 8mb using allocation block size of 4K bytes is 256 bytes, allocation block size can be as a large as 16K (32K on clones). For large disks I use either 4K or 8k allocations.? The Allocation size limits possible number of files as it sets a minimum granularity.? So for 8mb using 8K allocation block size limits the disk to 1024 files, for 4K it would be 2048 assuming DIRectory size can accommodate that.? The size of? things in the bios for a given disk as all sorts of interactions.? The CP/M Alteration Guide is rather vague on all that.. Andy Johnson-Larid CP/M Handbook gets into it and helps make it clearer. Once up as per earlier CP/M system getfile and putfile tools of my creation are use to transfer serially via USB serial cable to PCs or real serial (tm) to other non PC systems usually VAX, PDP-11, or CP/M. For the BIOS I use on many systems where the device is LBA rather than track sector I use sectors per track of 4 as the device is typically 512byte sectors and make tracks equal to the size of disk (8MB/512=16384).? Offset is usually 0000 as I typically boot from Eprom (copy ccp and BDOS from 8k eprom).? However offset is not part of the size of disk as literal 0th is the first sector that happens to be directory for X many sectors with data block after that. Hard disks are not removable during operating of system so checked entries will be zero (0) but is used for floppies to insure a media swap is caught before a write which would trash the directory. The next high memory cost item is the disk buffers typically equal to sector size or sometimes block size? I try to keep them small.? For example 512 bytes by 4 drives can easily eat up 2K of valuable ram in a basic 64K system.? Why?? They cannot be shared if doing a disk to disk copy havoc would ensue. That's important as high level languages like C, Pascal, and even assembles want ram to run? fast and most the minimum is 48K (ram from 100h to base of BIOS) as the BDOS and CCP are easily overlaid and reloaded. Sector skew only applies to floppies (rotational delay) and for hard disks and other modern media CF and SD zero (00) makes more sense.? Save having skew table or calculating it.? I stopped building in floppies when IDE hit the streets (as too small and salvage) and drives became cheap.? CP/M itself has a internal math error that limits it to 8mb.? P2dos, NovaDOS, Zrdos and a few others fix that at the cost of must be Z80 CPU.? For those 1GB is the limit and 32Mb partitions makes more sense.? The latter due to the flat file structure.? I've spent more than a little time inside CP/M (and enhanced clones) as sources have been available since 1980. Some of the buffers and other space eaters that the BIOS hides can be burred in mapped ram such as Z80MC has for the first 32K.? I've used that before in? a few of my machines where I strive for faster and larger available ram (usually 62K).? The other trick is if the EPROM is large? as in greater than 16K a bootable image of CP/M, Bios and a system monitor that will load it to ram. One block or mappable ram is low ram and others used to support the BIOS. FYI the z80MC will be paired with a small LCD Display and keyboard as a portable system on battery. Allison |
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Re: Where's the CPM files
Hi Josh,
Best place is the files section of the group. While use PCs and program them even the older systems are my thing. I still have the old don't you wish you have now what DEC had then. For that I boot the MicroVAX as The OpenVMS Language Senstive Editor LSE and cross platform systems are still cleaner than some of the current PCisms.? Linux made than less painful. The only time I've done SD so far I made FAT file of 256mb on a fresh 1GB device?so that its allocated sequentially.? Then located the staring Block number and addressed the blocks in it as LBA starting at xxxxxxH? to the PC its just a block that's allocated with whatever inside.? The system then doesn't need to know FAT at all.? The PC only created the larger container file and allowed me to know the stating address. The CP/M system populated the container file as sectors starting at xxxxxh.? The PC was involved but minimally to initialize (create Fat 32 container file) the disk. As to BIOS design and storage allocation its not obvious but Alloc is a bit map that has one bit per addressable block for the current allocation size.? I had to figure that out in late 1979 when I got CP/M2.2 after running 1.3 and 1.4 in prior years.? So Alloc map for 8mb using allocation block size of 4K bytes is 256 bytes, allocation block size can be as a large as 16K (32K on clones). For large disks I use either 4K or 8k allocations.? The Allocation size limits possible number of files as it sets a minimum granularity.? So for 8mb using 8K allocation block size limits the disk to 1024 files, for 4K it would be 2048 assuming DIRectory size can accommodate that.? The size of? things in the bios for a given disk as all sorts of interactions.? The CP/M Alteration Guide is rather vague on all that.. Andy Johnson-Larid CP/M Handbook gets into it and helps make it clearer. Once up as per earlier CP/M system getfile and putfile tools of my creation are use to transfer serially via USB serial cable to PCs or real serial (tm) to other non PC systems usually VAX, PDP-11, or CP/M. For the BIOS I use on many systems where the device is LBA rather than track sector I use sectors per track of 4 as the device is typically 512byte sectors and make tracks equal to the size of disk (8MB/512=16384).? Offset is usually 0000 as I typically boot from Eprom (copy ccp and BDOS from 8k eprom).? However offset is not part of the size of disk as literal 0th is the first sector that happens to be directory for X many sectors with data block after that. Hard disks are not removable during operating of system so checked entries will be zero (0) but is used for floppies to insure a media swap is caught before a write which would trash the directory. The next high memory cost item is the disk buffers typically equal to sector size or sometimes block size? I try to keep them small.? For example 512 bytes by 4 drives can easily eat up 2K of valuable ram in a basic 64K system.? Why?? They cannot be shared if doing a disk to disk copy havoc would ensue. That's important as high level languages like C, Pascal, and even assembles want ram to run? fast and most the minimum is 48K (ram from 100h to base of BIOS) as the BDOS and CCP are easily overlaid and reloaded. Sector skew only applies to floppies (rotational delay) and for hard disks and other modern media CF and SD zero (00) makes more sense.? Save having skew table or calculating it.? I stopped building in floppies when IDE hit the streets (as too small and salvage) and drives became cheap.? CP/M itself has a internal math error that limits it to 8mb.? P2dos, NovaDOS, Zrdos and a few others fix that at the cost of must be Z80 CPU.? For those 1GB is the limit and 32Mb partitions makes more sense.? The latter due to the flat file structure.? I've spent more than a little time inside CP/M (and enhanced clones) as sources have been available since 1980. Some of the buffers and other space eaters that the BIOS hides can be burred in mapped ram such as Z80MC has for the first 32K.? I've used that before in? a few of my machines where I strive for faster and larger available ram (usually 62K).? The other trick is if the EPROM is large? as in greater than 16K a bootable image of CP/M, Bios and a system monitor that will load it to ram. One block or mappable ram is low ram and others used to support the BIOS. FYI the z80MC will be paired with a small LCD Display and keyboard as a portable system on battery. Allison |
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Re: Where's the CPM files
Hi Allison, Welcome back!?? There has been an issue with my implementation of CP/M on both the S100 JAIR board and the Z80MC. I failed to understand one of the drive buffer spaces needed, the space needed to create a bit map of the clusters used/free. I followed the examples in the CP/M books and used 31 bytes which is the size required for the SSSD disks of 256,256 bytes. I have now rewritten the BIOS to expand these buffers to 512 bytes, enough for 8Meg disk file images. The BIOS uses SD Card FAT-16 format to reach the data on the Card.? I could have just used the SD Card in it's raw form, but then you'd need special programs to access the card from a computer.? Since I still use PC's, I choose to use the well established FAT-16.? The BIOS can read and write data into the FAT-16 disk images, but it cannot create any FAT-16 files or extend those files.? It doesn't know how to look for a free cluster and add it to the file chain, or even how to change the file size.? It simply uses the space of the file as it's already allocated in the FAT-16 table.? The BIOS counts through the clusters of the image file as CP/M counts through the sectors and tracks.? There is no skewing, it's 1 to 1.?? I will send you the files directly rather than waste space in the 1802 forumn. Cheers, Josh
On Tuesday, December 5, 2023 at 09:20:54 a.m. EST, ajparent1/kb1gmx <kb1gmx@...> wrote:
Hello all... She's back! It been a while and life intervened...? One of the things was getting a Z80MC to play with. I have over a dozen CP/M systems and a few of my own creation both hardware and highly modified software. CP/M is a very malleable OS and can support more than most think or have tried. So now I have a real Z80MC and the software is done is such a way as to be different from the BIOS and loaders of my experience.? Back then it was floppy, hard disk, Eprom based, and of course IDE/CF based,? With that FAT was never a consideration. I find FAT too tightly tied to PCs and equally as fragile as? CP/M allocation scheme. The other is that FAT offers a hierarchical file system and CP/M can't/doesn't use it. It something I'd like to add to CP/M, that is a way to like from one device/Drive to another (especially on large media). The other is my system the typical disk is 8MB (or 32mb for ZRDOS) and multiple partitions.? ? If all goes well it will be a self development environment for a simpler OS like NSDos, the goal there is to release it from hardware NS* MDS hard sector disk. So it will be a playground for experiments started in some case over 45 years ago. Allison |
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Re: Where's the CPM files
Hello all...
She's back! It been a while and life intervened...? One of the things was getting a Z80MC to play with. I have over a dozen CP/M systems and a few of my own creation both hardware and highly modified software. CP/M is a very malleable OS and can support more than most think or have tried. So now I have a real Z80MC and the software is done is such a way as to be different from the BIOS and loaders of my experience.? Back then it was floppy, hard disk, Eprom based, and of course IDE/CF based,? With that FAT was never a consideration. I find FAT too tightly tied to PCs and equally as fragile as? CP/M allocation scheme. The other is that FAT offers a hierarchical file system and CP/M can't/doesn't use it. It something I'd like to add to CP/M, that is a way to like from one device/Drive to another (especially on large media). The other is my system the typical disk is 8MB (or 32mb for ZRDOS) and multiple partitions.? ? If all goes well it will be a self development environment for a simpler OS like NSDos, the goal there is to release it from hardware NS* MDS hard sector disk. So it will be a playground for experiments started in some case over 45 years ago. Allison |
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Re: 3D Printed Case for Z80card with top.
开云体育I like the cover design too. For my MC, I built a separate LiPO battery/Bluetooth module into another Altoids can and the Z80MC sits in the lid and connects to the battery with a cable. ? Rich ? -- Rich Cini ? ? On 1/5/22, 11:10 AM, "bill rowe" <[email protected] on behalf of bill_rowe_ottawa@...> wrote:
? That looks great - very functional.? Is there room for a battery? |
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