– Reduced effect on MCL updates 

– Better availability 

GLYPH<SM590000> Faster Dynamic Memory Relocation engine: 

– Enables faster reallocation of memory (2x faster) that is used for LPAR activations, CDR, and concurrent upgrade 

– Provides faster, more robust service actions 

GLYPH<SM590000> Dynamic Time Domain Reflectometry (TDR), which was static 

Hardware facility that is used to isolate failures on wires provides better FRU isolation and improved service actions. 

## 9.4 Reducing complexity 

GLYPH<SM590000> Universal spare for PU SCMs and SC SCMs and processor drawer 

z14 ZR1 continues the z13s enhancements that reduced system complexity. Specifically, simplifications were made in CPC drawer technology, which reduces the number of CPC drawers to one and RAIM recovery in the memory subsystem design. Memory DIMMs are not cascaded, which eliminates the double FRU call for DIMM errors. 

Independent channel recovery with replay buffers on all interfaces allows recovery of a single DIMM channel, while other channels remain active. More redundancies are incorporated in I/O pins for clock lines to main memory, which eliminates the loss of memory clocks because of connector (pin) failure. 

## 9.5 Reducing touches 

The following RAS enhancements reduce service complexity: 

GLYPH<SM590000> Continued use of RAIM with ECC. 

GLYPH<SM590000> No cascading of memory DIMM to simplify the recovery design. 

GLYPH<SM590000> Replay buffer for hardware retry on soft errors on the main memory interface. 

GLYPH<SM590000> Redundant I/O pins for clock lines to main memory. 

IBM Z RAS efforts focus on the reduction of unscheduled, scheduled, planned, and unplanned outages. IBM Z technology has a long history of demonstrated RAS improvements, and this effort continues with changes that reduce service touches  on the system. 

Firmware was updated to improve filtering and resolution of errors that do not require action. Enhanced integrated sparing in processor cores, cache relocates, N+1 SEEPROM and POL N+2 redundancies, and DRAM marking also are incorporated to reduce touches. The following RAS enhancements reduce service touches: 

GLYPH<SM590000> Improved error resolution to enable filtering 

GLYPH<SM590000> Enhanced integrated sparing in processor cores 

GLYPH<SM590000> Cache relocates 

GLYPH<SM590000> N+1 SEEPROM 

GLYPH<SM590000> N+2 POL 

GLYPH<SM590000> DRAM marking 

