First, let me say I understand that 'recommendation style' questions can be very subjective, but I believe there is enough value in a few good beginner resource pointers that others could benefit from any answers generated by my question. That said,

I'm looking for a recommendation for a straightforward Disk/Sector editor for the Commodore 64 with a 1541 disk drive. I've found some utilities for windows and other operating systems that will allow examination of D64 images but I'm looking for something running on the C64 itself.

My goal is to use this inside VICE and on actual hardware to inspect both physical disks and some disk images I converted last year. I want to walk from the directory to the start of a given file, examine the leading bytes of the file (which should indicate the memory load address for the file contents) and walk the chain of blocks/sectors that comprise the file contents.

I've gotten rusty with old age, and while I remember spending many long nights in front of Supermon64, I can't for the life of me remember what my go-to solution was for examining disks.

As always, any input is greatly appreciated!


The Epyx Fast Load Cartridge did much more than just increase the speed of data between a 1541 disk drive and a Commodore 64. Features included a Machine Language Monitor and Disk Tools.

The Disk Tools, accessed by pressing the British Pound Sterling symbol (£) at the READY prompt allowed the following features: Directory, Copy Disk, Disable Fastload, Edit Diskette, and File Tools (Directory,Copy,Delete,Lock,Unlock,Rename)

NOTE: there is some controversy about the mention of the British Pound Symbol: In the manual for the Epyx Fast Load and on the Commodore 64 Keyboard, the symbol is described as the British Pound Symbol and is signified by the symbol # in transcripted versions of the manual, since having to type ALT-0163 may not have occurred to the transcribers. Found a scan of the original manual here, thanks to retro-commodore.eu which has the correct original symbol:


The Disk Editor may be a tool useful to you - I never used it since I was mainly interested in games, but the Fast Load cartridge is ubiquitous and commonly available. Not sure how to mount one in VICE. You can easily obtain a FastLoad manual with a cursory google search.

  • The pound symbol that activates the disk tools is £ - unless there are different versions of the cartridge – Wumpus Q. Wumbley Oct 21 '17 at 16:34
  • @WumpusQ.Wumbley there might be, or the OCR of the scanned manual went wrong, but a lot of the documentation I have seen indicates the # symbol - maybe there is a difference between the "pound symbol" and the " British pound symbol". – PhasedOut Oct 23 '17 at 12:41
  • @PhasedOut, thanks for the response. I didn't know the Epyx cart would do all those things. I might have to get one just to have kicking around. In the end I settled on DI-SECTOR 3.0. See my reply post for full details. – Geo... Oct 29 '17 at 20:58

After doing some research, and some downloading, and some experimenting, I eventually settled on DI-SECTOR 3.0 from StarPoint Software (1985).

enter image description here

What sold me on DI-SECTOR was the Text and Hexidecimal representations for the current sector are both on-screen at the same time.

enter image description here

Many of the sector editors I looked at would only show the textual representation for the current sector and then only display the hex value for your current cursor position, which seemed overly cumbersome. I find the full display of both views to be far more friendly and closer to what I would expect from a modern hex editor.

DI-SECTOR 3.0 was easy enough to navigate, and with a copy of Inside Commodore DOS it was simple enough to traverse the BAM, directory entries, file blocks, and do repair work to damaged data.

Hopefully this helps someone else in the future! Enjoy!

  • Good find! That looks like it its going to be the ticket. Where did you find it? – PhasedOut Oct 30 '17 at 12:20
  • Thanks! Given the copyright gray-area nature for most of the retro disk images out there, I'm always a bit leery to post direct links. However, I would say that googling the phrase "Di-Sector v3.0 was released by Starpoint Software in 1985" (include the quotes) would probably point you in the right direction ;-) – Geo... Oct 30 '17 at 14:31
  • I wonder if any editors of that era used hi-res mode for the display to show two hex bytes every 24 pixels? Most displays would not legibly show one bytes per 8-pixel character, but four hex digits for every 24 pixels could be quite readable even on a rather crummy display. Sixteen hex bytes could then fit on the same line as 16 8-pixel characters.. – supercat Oct 30 '17 at 18:54

I can recommend Reconnaissance. It's easy to use and also has a neatly arranged hex and ascii view. It is also what I used back in the days.


^ Only very few sector editors offer such wide petscii lines. This increases readability - each directory entry equals one line. The program "sector ed." starts at track $13, sector $00. The filetype is standard prg as defined with the $82 left of it.

Just like you, I need a sector editor (my nordic power cartridge sometimes saves files with a wrong load-adress to disk).

So I tested literally a dozen other sector editors today. In Vice and/or on my physical machine - just to have a look. (It took quite a while ;) One of the best was "Satans Seed" aka "Satans Cracker" by "the deacon". Don't look at me, I didn't label it that way ;)

seed screenshot

If you want small size the winner in my opinion is disc-doctor-V3 by kevin pickell using only 15 blocks.

enter image description here

You maybe can find these programs if you g**gle for "commodore.software" and "disk editors", but I'm sure searching the internet for the program names will work, too.

  • 1
    Welcome to Retrocomputing Stack Exchange. This is a very detailed answer; thanks! I hope you continue to contribute to the site. – wizzwizz4 Dec 9 '17 at 14:37

Another way that I just recently learned although I use cartridges since "the days" is:

If you have a cartridge like the Nordic Power or the Action Cartridge+ you can use the sector editor that is built into the assembler monitor. It's less comfortable but way quicker and you don't have to load a program.


  • Enter the monitor with F2
  • The monitor command "@BR track sector adress" will load a sector (256 bytes) to given memory adress.
  • For example "@BR 12 01 40" will load track $12, sector $01 to C64 memory at $4000 (this is the first block of the disk directory)
  • Like always "M 4000" or "I 4000" or "I* 4000" will let you view and edit the memory.
  • If you changed something and want to write it back to disk just use "@BW track sector adress"
    f.e.: "@BW 12 01 4000"

You can do exactly the same in Vice when you've got a .crt image file of the cartridge and mount it.

Screenshot - Sector editor Screenshot - Sector edited Screenshot - @BR

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