Reference
ACPI and PNP identifiers
Use the UEFI Forum's ACPI ID and PNP ID registries as a reference to translate the prefix of any ACPI identifier, or the three-letter manufacturer code from a monitor's EDID, into the company name, along with the date it was approved.
ASCII table
Review printable and control ASCII characters along with their decimal, hexadecimal, octal and binary values for low-level debugging.
Cron expression reader and editor
Use the cron editor as a practical reference to interpret fields, presets and upcoming runs when documenting scheduled tasks.
DNS record types
Look up DNS record types—address, mail, alias, zone, service, and security—with their name, what they are for, and examples, when configuring domains or diagnosing resolution.
HTML entity table
Search characters, symbols and HTML entities to copy their correct representation when working with web content or documentation.
HTTP status codes
Look up HTTP status codes by family to understand API, server and browser responses during debugging or technical documentation.
Linux error codes: errno, signals and exit codes
Search errno values, signals and exit codes by number, name or message, with the Linux and macOS values, and decode codes such as 137 or 143 from Docker and Kubernetes.
List of TCP and UDP ports
Search by number or service among the TCP and UDP ports most used in servers, networks and development: web, email, databases, remote access, VPN, containers and more, with the unencrypted ones flagged.
Manufacturer lookup by MAC OUI
Use the IEEE OUI registry as a reference to translate the prefix of any MAC address into the manufacturer's name, and to see whether the address is unicast or multicast and whether it is globally assigned or locally administered.
MIME types
Find MIME types and associated extensions to configure HTTP responses, file validations, uploads and content metadata.
PCI identifiers (vendor/device)
Use the pci.ids catalog as a reference to translate any PCI Vendor ID and Device ID to the chip name, and the subsystem to the specific board model.
SMTP reply and status codes
Search SMTP reply codes (2xx, 3xx, 4xx and 5xx) and enhanced status codes such as 5.1.1 or 5.7.1 to understand why an email bounced or was delayed, or paste the full server response.
USB identifiers (VID/PID)
Use the usb.ids catalog as a reference to translate any USB Vendor ID and Product ID to the manufacturer and product name, with the version and date of the consulted catalog.
Visual chmod permissions calculator
Calculate chmod permissions for Unix and Linux by checking boxes for user, group, and others, include the special bits setuid, setgid, and sticky, and get the octal number, symbolic notation, and chmod command ready to copy.
Windows error codes: Win32, HRESULT, NTSTATUS and blue screens
Search Win32, HRESULT, NTSTATUS and blue screen codes by value, name or text, with Microsoft's description in your language and the HRESULT split into its fields.
About this category
Reference tables gather data that people look up again and again and that is not worth memorizing: what an HTTP status code, an SMTP reply or a Windows or Linux error code means, which HTML entity matches a symbol, the ASCII value of a character or the MIME type of a file extension.
Each table has search and filters to get to the data quickly, plus a description of each entry. The category is rounded out by DNS record types and their use, the most common TCP and UDP ports with their associated service, and shortcuts to MAC vendor lookup, USB and PCI identifiers, cron syntax and chmod permissions.