maximal size of TRD image

[VELESOFT]

Maximal size of TRD image - calculation:

- max. 16 sectors per track
- max. 256 tracks (0-255) per one disk side
- max. 2 disk sides

complette size:
16(sectors) x 256(tracks) x 2(sides) = 8192 sectors x 256 bytes(sector size) = 2048 kB = 2 MB.

Exist TRD creator(utility) with support this max. size limit ? :v2_conf3:
Can ZX emulators on PC work correct with bigger TRD images than 640kB ? :v2_eek:

I find on my HDD any TRD images with different length than 640kB (720kB and more < 640kB) :v2_conf2:

VELESOFT

[GriV]

Usually no.
Unreal ZX emulator can't use large (more than 83 tracks) trdos disk images - internal checking disable all tracks after 83 (even if it presents). And size of .TRD files can't be greater than 640K.
SCL files can contain more than 80-84 tracks, but you cant' is it because of track checking.

Supported both 640K images and cutted of .TRD files.
Cutted images does not contain zero-filled tracks at end of disk, at all.
I never (maybe I forgive it?) see .TRD images more than 640K.

Current utilities (AMD01, SpectrumNavigator, plugins for FAR) does not support larger than 640K size of .TRD files.

[boo_boo]

are you speaking about maximum capacity that TRD file format can provide?
yes, it may hold that much data, but this is incompatible with any ZX/TR-DOS emulators, since most capacious media supported by TR-DOS hardware/software is DS/DD floppies (standard capacity: 80tracks x 2sides x 16sectors x 256bytes = 640kB, max capacity: 86tracks x 2sides x 16sectors x 256bytes = 688kB)

[VELESOFT]

This is TRD image created on SPECTRUM NAVIGATOR on PC (size 1MB = 128 tracks):
http://velesoft.speccy.cz/other/1mb_trd.zip :v2_jawdr:

And this is bigger TRD images finded on my HDD:
http://velesoft.speccy.cz/other/big_trd_images.zip :v2_conf2:

VELESOFT

[boo_boo]

it seems that these files (except for 240ds.trd which is simply broken) were made with PC software that doesn't care whether TRD images are valid.
none of ZX/TRDOS emulators can deal with extra space at the end of these images, though some of them may be able to handle first 640/688kB.

[elf/2]

Current utilities (AMD01, SpectrumNavigator, plugins for FAR) does not support larger than 640K size of .TRD files.

after looking on xTRD 1.0 sources I see that it should support big .trd images. the plugin checks for tr-dos signature (0x10 at 0x08e7) and that file size is divisible by 16*256

at the same time it does not allow creation of images bigger that 640K

[Antipod]

Maximal size of TRD image - calculation:

- max. 16 sectors per track
- max. 256 tracks (0-255) per one disk side
- max. 2 disk sides

complette size:
16(sectors) x 256(tracks) x 2(sides) = 8192 sectors x 256 bytes(sector size) = 2048 kB = 2 MB.

Exist TRD creator(utility) with support this max. size limit ? :v2_conf3:
Can ZX emulators on PC work correct with bigger TRD images than 640kB ? :v2_eek:

I find on my HDD any TRD images with different length than 640kB (720kB and more < 640kB) :v2_conf2:
VELESOFT

в принципе возможно - пчему нет?
только, вроде, существующий спековский софт не поддержит дисков на 256 дорожек, максимум - 128, птому как, если склероз не подводит, под сторону и номер дорожки обычно отводится один байт.
могу и ошибаться.

вроде, даже при записи дальше 128 дорожки косяк будет, просто потому, что в каталоге под дорожку/сторону тож один байт...

[VELESOFT]

в принципе возможно - пчему нет?
только, вроде, существующий спековский софт не поддержит дисков на 256 дорожек, максимум - 128, птому как, если склероз не подводит, под сторону и номер дорожки обычно отводится один байт.
могу и ошибаться.

вроде, даже при записи дальше 128 дорожки косяк будет, просто потому, что в каталоге под дорожку/сторону тож один байт...

Yes, thank. One byte = 256 x 16sectors(4kB) = 1024kB=1MB.
Only FDC controller(VG93) can use 256(tracks) x 2(sides) x16sectors(track size for trdos) = 256x2x4kB = 2MB disk image(but only first 1MB is usable in TRDOS).

VELESOFT