Serial sniffer would tell you. Xmodem probably limited to 64k by protocol without extensions.
Taking 10 minutes seems slow. What speed? -- John. On Sat, Feb 25, 2017 at 1:55 PM Brian White <[email protected]> wrote: > Random model 600 discoveries while trying to test the new ram boards more > rigorously. > > Idea was to: > > Populate both slots, which makes a little over 220k available. > > Generate about 256k of random binary data on a modern machine. I just > copied 256k of random stuff and used gpg on it a few times randomize it > thoroughly. > > Xmodem the blob to the 600 until it aborts. > > Xmodem the blob back to the pc. > > Use dd to copy out a truncated excerpt from the original blob of exactly > the same size as the blob that came back from the 600. > > Binary compare the two truncated blobs. > > > I encountered 2 things: > > You can't xmodem more than 64k in one file. > > So I split the 256k blob into 4 64k blobs and discovered the next thing. > > You can't *actually* xmodem more than 64k *minus one byte*, in a single > file. > > If you try to send a file over 64k and allow telcom to truncate it at 64k, > or if you try to send a file that is exactly 65536 bytes, you will transfer > 65536 bytes both ways, and neither side of the connection will issue any > warnings or errors. Both TELCOM and the xmodem util on the modern machine > will say everything went fine. But if you transfer a 65536 byte file from a > pc, to the 600, and back, the final byte will be changed from whatever it > was to a 0x20 space. All other bytes are preserved. > > If you transfer a file 65535 bytes or less, the file makes it both ways > 100% accurate. > > I don't yet know when the change takes place. Is it when telcom receives > the file from the pc, or when telcom sends the file to the pc? Both? There > are a few ways to test the individual parts, just it's soooo sloooow. It > takes about 10 minutes to transfer 64k. > > I think this mostly proves out the ram boards, as well as can be without > an actual ram test program. To really be sure, I should swap the 2 boards > between slots 1 & 2, and repeat the whole process. Ugh. > > -- > bkw >
