Microcode terms The microcode features the following characteristics: How the driver, bundle, EC stream, MCL, and MCFs interact with each other is shown in  Figure 11-20. GLYPH<SM590000> The driver contains engineering change (EC) streams. GLYPH<SM590000> Each EC stream covers the code for a specific component of z14 servers. It includes a  specific name and an ascending number. GLYPH<SM590000> The EC stream name and a specific number are one MCL. GLYPH<SM590000> MCLs from the same EC stream must be installed in sequence. GLYPH<SM590000> MCLs can include installation dependencies on other MCLs. GLYPH<SM590000> Combined MCLs from one or more EC streams are in one bundle. GLYPH<SM590000> An MCL contains one or more Microcode Fixes (MCFs). Figure 11-20 Microcode terms and interaction 432  IBM z14 (3906) Technical Guide