YMODEM (fastest)

Owned by patters
Last updated: Jun 15, 2024
2 min read

Although EazyLink2 offers more features and is more tolerant of varying serial port hardware configurations, YMODEM file transfers reach triple its maximum speed - achieving 3K/sec at 38400bps regardless of OZ version. This is because the YMODEM implementation does not use the OZ serial driver, so it is not limited to lower baud rates by the driver issues in the original Cambridge ROM versions. Also, by increasing the block size from 128 bytes to 1K and by batching multiple files together into a single session, YMODEM significantly increases communication efficiency.

Transferring the 256KB of OZ 4.7.1 ROM files will take around 1 min 25 secs - something that is an agonising order of magnitude slower on an unmodified Z88, constrained as it is to 9600bps in EazyLink2, or slower still if using ImpExport.

Z88 Setup

There are several ways to perform a YMODEM transfer on the Z88, which will depend on OZ version.

OZ Version

Popdown

Method

OZ Version

Popdown

Method

5.0

Filer

TAB to select multiple files, send batch using â—‡ S B. Receive a batch into the current directory using â—‡ R B.

5.0

Shell

sb -k filenames to send. rb -c to receive.

4.5 - 4.7.1

ImpExport

Y for YMODEM, then C for CRC, then K for 1K block size. Wildcards are permitted for batch sending. ESC to exit.

2.2 - 4.4.1

XY-Modem

Y for YMODEM, then C for CRC, then K for 1K block size. Wildcards are permitted for batch sending. SHIFT+ENTER to exit.

Remember to set the serial transmit and receive baud rates to 38400, and to disable Xon/Xoff, in Panel popdown (â–¡ S)

Computer Setup

Consult the following guides:

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