[GTALUG] Printing Problem(s)

[Stewart C. Russell]

On 2020-04-17 10:23 a.m., D. Hugh Redelmeier via talk wrote:
> 
> I don't know enough about IPP, but I suspect that the actual data
> could be in PCL or PostScript or something else …

It's a bit more clever than that. All IPP/AirPrint printers *must* 
support a basic bitmap format that is open and well-defined. IPP 
printers advertise what formats they support: querying my Brother 
printer (using ipptool) says it handles image/urf and image/pwg-raster. 
Some can also accept PCL and PDF.

The internal routing of CUPS print jobs is done as PDF. CUPS is rather 
lovely unless you want to see the internals. IPP allows printer 
manufacturers to change hardware completely on the same model and still 
keep working*. Since the most important question for any printer sold 
these days is "Can I print from my iPhone?", IPP/AirPrint support is not 
going away. Google Cloud Print, btw, *is* going away this year.

(Apple owns CUPS, and AirPrint is their trade name for IPP.)

The "dual core, 0.8 MHz" is more likely to be "dual core, 0.8 GHz". Dual 
core Qoriq boards (typically Power, but sometimes ARM) are what powers 
so much hardware we take for granted.

cheers,
  Stewart

*: this makes sites like LinuxPrinting completely useless, alas, but 
makes for cheaper printers.