80-Bus News

  

November–December 1983, Volume 2, Issue 6











Page 62 of 67











62

If you get nulls in front of the -HEX file on the receiving machine, use [Hu] as a final parameter on the receiver command line. LOAD and UNLOAD only work on the same DRIVE as the .COM or .HEX, so this sets an effective limit to the size of the file you can handle – roughly 25% of your drive capacity, as the .HEX file is 2.81 times the size of the original .COM file. UNLOAD only works on .COM files, so if your file is of another type, then REN it to a .COM type, remembering to change from a .COM type at the receiver.

What happens during transmission is that the transmitter sends a character, then waits for the receiver to transmit the character back again. The receiver gets a character and retransmits it immediately. If either machine is busy, then the acknowledgement does not occur, but the unread transmitted character is held in the UART buffer until read.

I hope that this very simple method of transmission is as much use to readers as it has already been to me – 400k transmitted, with no errors!

LISTING 1 ---- UNLOAD.HEX

: 1001 00002 A06002BF9C31 101 7H1 2231 30DC 20801 28 21001 10000921 5C001 11 FO1 OFO9CDO801C34601 0071 : 1001 2000000000000000000043 4F 4DOOO0000000F0 11001 S000DD0DNN0ONDNN0NNDNDN0000000000000000BF : 1001 4000ED03000400000 3B601 244201 EB2A44017A :100150007D937C 9ADAIFO!1 210000224401 EB2A4220 : 1001600001 7B957A9CD291 01 244001 1 9EBOH1 ACDAO 2 1001700005001 11 FO10E1 4CDO0500B7C 28B01 1 1 8OBF + 10018000002A4401 19224401 035D01 244401 224286 11001900001 1 1 80000E1 ACDO50021 0000224401 EB60 : 1001 A0002A4001 1 9EB2A4201 7DB43H1 AC81 AQAA49A 11001 BOOO01 23224401 C9OAF322B01 323F01 21000447 : 10010000224201 224401 OKOF 1 1 1FO1 CD05003C0C245 : 1001 DOOOEDO1 OF091 1DD01 CDO5O0OCSOO0OODOA4LES 1 : 1001 H0004F204946494045204649404524215C0056 : 1001 FOO01 1 FBO1 OFO9CDO801 C3220200000000001E : 10020000000000004.8455800000000000000000009 2 10021 DOODDDDDDDDDDN0DND0000000000ED070004E6 : 1002200000000 3A502F52A1 EO2EB2A20027D937C62 : 100230009ADA950221 0000222002EB2A 1E027B9509 : 100240007A9CD287022A1 C021 9EBOE1 ACDO5001 1E6 : 10025000F B01 OF1 5CDO500B7C 268021 1 80002A20EF 210026000021 9222002C33A020E091 1’7402CD0500C0 : 10027000F 1 CZ00000D0A444.9534B2046554C4C3AFB : 100280002047 46494045241 1 80000E1 ACDO50021 OF :100290000000222002EB2A1 C021 9EBF1 1 224200294 : 1002A00023222002C 9AF320702321 BO221 0004229 : 1002B0001 £0221 00002220020EK1 31 1 FBO1 CDO500B9 : 1002COOO0E1 61 1 FBO1 CDO5003CC2ED020E091 1D73F : 1 002D00002CDO500C ZO0000DOA4E4F2044495220B4 1 1002E000535041 43453A204F4649404524210001 93 :1002F00006001 16D001A1 3D630DA1 403FEOADAOB69 :1003000003D607DA1 403FE1 OD21 403292929294F32 110031 O0009C 3F50222EA03CD4901 CASAOSF53EB5A50 : 100320000 D2502AF32RC033E1 OCD4EO33ABBOSCDAB


This is an OCR’d version of the scanned page and likely contains recognition errors.











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