Hi Murray,
Your (yet another) excellent overview inspired me for a small question.

InterSystems IRIS uses direct I/O for database and journal files, which bypasses the filesystem cache.

Our in-house IRIS starts with messages: 
 

Startup of InterSystems IRIS [IRIS for UNIX (Ubuntu Server 20.04 LTS for x86-64) 2022.1.3 (Build 668U) Fri Apr 7 2023 12:46:56 EDT]
	in /vol/IRIS/bin/
	with mgr: /vol/IRIS/mgr
	with wij: /vol/IRIS/mgr/IRIS.WIJ
	from: /vol/IRIS/mgr/
  OS=[Linux], version=[#236-Ubuntu SMP Fri Apr 11 19:53:21 UTC 2025], release=[5.4.0-216-generic], machine=[x86_64]
  nodename=[irisunicodefull.myhome.com].
  numasyncwijbuf: 2, wdwrite_asyncio_max: 64, wijdirectio: on, synctype: 3
  System Initialized.

Are there some signs that direct i/o is used for database access?
If not, how can one recognize which type of i/o (direct or async) is used for each kind of IRIS i/o (database, WIJ, journal)?

Set ^LOG("xUpload",+$Horolog,patId)=status_"^"_SQLCODE_"^"_$Get(%msg)

What if there is more than 1 error with the same patId per day?
Using date/time e.g.:

Set^LOG("xUpload",+$Horolog,$piece($horolog,",",2),patId)=status_"^"_SQLCODE_"^"_$Get(%msg)

is usually more reliable.

Hi Robert,

Why did you crossed out Function method? It seems to be a supported one.